In airports in every corner of the world – from the biggest international hubs to the smallest, far-flung outposts – the downing of the Malaysian Airlines flight MH17 in eastern Ukraine has been on the lips, or in the thoughts, of hundreds of thousands of travellers boarding planes to holiday and business destinations.
The tragic deaths of nearly 300 people on a flight from Amsterdam to Kuala Lumpur as it crossed over the war-ravaged Donetz region has brought the perils of aviation into sharp focus at a time when America had also ordered a major tightening of security amid fears that al-Qaeda has produced new bombs with which to target aircraft.
Factor in the disappearance of another Malaysian plane, MH370, in March and it's little wonder that concerns about the safety of air travel are growing.
It's estimated that, around the world, more than three billion people will take flights this year, but experts say there's little evidence that many of them will be deterred from travelling because of the latest crises, due to a combination of necessity and "it won't happen to me" stoicism.
Just 24 hours before the Ukraine disaster, the Belfast Telegraph was given an insight into the operation of Belfast International Airport, where businessmen, holidaymakers, Lourdes pilgrims and even Belorussian footballers were among upwards of 11,000 travellers passing through.
The conveyor-belt of passengers in the check-in and arrival halls was almost non-stop, but even though to the untrained eye it might have seemed tantamount to a recipe for chaos, no one at the airport was getting aerated.
Even at the air traffic control tower, where the responsibility for so many travellers' safety might have brought lesser mortals out in a cold sweat, it was an oasis of calm.
The work there normally goes on below the radar, so to speak, for the four million passengers who annually use one of Northern Ireland's best-known destinations, which, perversely, is also one of its least-known in terms of what happens behind the scenes.
In many ways, it's like an iceberg with only a fraction of it ever seen by the travelling public, who take for granted a complex and highly choreographed, chess-like operation, which has more than 4,500 people working there to make sure the pieces are all in place.
And it's an airport which hardly ever sleeps, particularly in the summer. First thing in the morning, it's the commuter flights, especially to Britain, which ensure the terminal is crowded.
They're supplemented throughout the day with holiday flights and at night, while there are charter planes landing from the likes of Turkey and Greece into the early hours, it's the air cargo terminal which really comes into its own, handling 50,000 metric tons of freight every year.
On Wednesday, as holidaymakers turned up to jet off for weeks, or fortnights, in hotspots like Cyprus, Lanzarote, Portugal, Egypt, and mainland Spain, the BBC's Julian O'Neill was there to report on Richard Branson breaking Virgin territory with a new limited summer service from Belfast to Florida. Business development director Uel Hoey was telling him that the International hoped Virgin would consolidate and expand the flights.
Hoey told me that the airport's traffic was up on last year and that other recent announcements of new flights to Las Vegas, Iceland, Bordeaux and Jersey had been major bonuses.
Hoey, who started off at the airport as a temporary information desk assistant more than 25 years ago after responding to an advertisement in Ballymena Jobmarket, also sent out a "watch this space" hint of even more services taking off in the coming months.
"We are working along with Government in order to pull in some important routes and destinations for the overall benefit of tourism and the economy," said Hoey, who added that he was also liaising with Stormont to prevent a repeat of the decision by United Airlines to stop their New York service for nine weeks over the winter period.
The attractions of Dublin airport have lured thousands of Ulster travellers and George Best Belfast City Airport has been another challenge. But Hoey says, "Competition is a fact of life and we want to grow this airport. We have new shareholders on board and they are keen to see the airport develop the footprint and the number of services we have.
"We recognise the size and scale of Dublin airport, but we're here to provide a service to two million people in our catchment area who want to fly from their own doorstep."
The International has its critics however, and near check-in, Radio Ulster's Linda McAuley was interviewing travellers for today's On Your Behalf consumer programme about the overall costs of holidays and the airport experience.
One of the major concerns was over the cost of car parking. Linda said: "Most people thought it was too dear.
"Many of them got lifts and they resented having to pay £1 to go through. Others thought that public transport was unreliable and got taxis instead. Excess baggage charges also annoyed some folk."
Nearby, Aodhan O'Donnell, from the Northern Ireland Consumer Council, was promoting a new podcast about travellers' rights, which can be found at the click of a button on smartphones and tablets.
Trying to ensure that the International's customers have little to complain about is Rod Haskins and his team, who man the Operations Control centre from where the parking of aircraft is managed and the overall supervision and policing of the high security terminal is conducted.
Officials survey a huge bank of monitors which relay CCTV images from every imaginable corner of the International and radio links keep staff in contact with other staff across the site and further afield if necessary.
As we talked a "first stage" fire alarm sounded and staff were dispatched to a store to investigate. But it was quickly decreed that it was nothing to worry about and no evacuation was ordered.
Haskins, a former fire office at the International, said the control room was manned 24 hours a day.
He said: "Today we have about 120 passenger flights coming in and out plus 20 freight flights at night and then there are military and police flights as well, plus private jets and medical planes, too.
"But you never know when we might get diversions from other airports, as well." He added that the success of the airport relied heavily on the good working relationship between the International and its partners, including the airlines, the handling agents and the commercial operations, including the independent shops, bars and cafes around the Aldergrove site.
"We want to keep everything moving all the time," said Haskins, "As well as the terminal and the apron, we are also responsible for the airfield itself.
"Air traffic control the aircraft, but we are in charge of ensuring the airfield is safe and complies with all the rules and regulations.
"We carry out inspections every four hours and more if there's rain or snow in wintertime. We are looking for faults on the runway, or contamination, or foreign objects like a plastic bag, or even Chinese lanterns which have wire in them.
"We also manage the environment right around us for 13 kilometres ensuring that the netting on rubbish facilities for example is well-maintained so that it doesn't end up on the airfield."
The control of animals like hares and birds is also crucial.
A worker spends his days scaring them off with the likes of flares, or playing recordings of distress calls from other birds.
In the air traffic control building operated by a worldwide firm called NETS Holdings, the general manager for Belfast, Martin Ruddy, explained that there were three different kinds of officials – the more visible tower controllers up top, approach controllers and en-route controllers.
They all have access to up-to-the-minute data from not one, but two radar heads at Aldergrove, enhancing the level of information available on the controllers' high-tech screens which give a pictorial representation of the planes in their airspace backed up by a series of contingency fail-safes in case something should go wrong.
Air traffic staff at Aldergrove work closely with their opposite numbers at the City airport to co-ordinate the huge numbers of planes arriving in or departing from Northern Ireland.
Not surprisingly, the team of 22 controllers and their assistants never stop learning.
They study for up to two years at a specialist college followed by intensive on-the-job training under the supervision of mentors. And everyone gets annual updated instruction in emergency procedures.
The workloads are carefully regulated. Ruddy said: "Our people do a minimum of seven hours and a maximum of 10-hour shifts, but they must have a half-hour break every two hours."
Ruddy admitted it can be a stressful job.
"But the stress doesn't just come from the number of aircraft, but from the complexities, as well," he said.
"In bad weather, for instance, everything slows down and we are busy trying to co-ordinate slots times and taking calls from the airlines in a bid to provide the best possible service."
Next door to the NETS building is the Aldergrove fire station, where massive, 36-tonne futuristic-looking engines stand ready to deal with any emergencies with onboard reserves of foam and upwards of 12,000 litres of water, compared to a normal Northern Ireland Fire and Rescue Service engine capability of 1,800 litres.
Forty-seven fire officers who are employed at the International also have a series of health and safety and first aid duties around the Aldergrove site and spend a lot of time training and carrying out daily inspections and maintenance checks on their appliances.
The fire team can respond to any emergency in around two minutes and station commander Clifford Johnston said: "Early intervention after an aircraft crash is key especially as planes have so much fuel and that's why our big vehicles are designed the way they are to empty their tanks as fast as possible."
So far the International fire crews have never had to deal with a major disaster.
And that's just the way they hope it will stay.
From families to footballers, pilgrims to party-goers
Limavady couple Shaun and Joanne O'Brien were so impressed with their break to Lanzarote without their children four months ago that they decided to head back for a family holiday.
They brought their daughters Kirsty (10) and Lauryn (15) with them for a week-long break in a hotel in Puerto Del Carmen.
The family had considered flights to Portugal from the City of Derry airport, but the timings didn't suit them.
“And, besides, it's only about 40, or 45, minutes down the road to the International,” says Shaun.
No fewer than three flights of pilgrims from Lourdes in France arrived back at Belfast International Airport on Wednesday.
Among them was Shauna Quinn, from Moortown, Co Tyrone, who has a physical disability.
She says: “It gives me the courage to cope every day, but when you go there your worries just seem to lift.”
But Shauna said her spiritual well-being had also been uplifted by her fourth trip to Lourdes.
Her mother, Bernadette, accompanied Shauna on the trip, which was organised by Kathleen McCann of the Magherafelt-based Our Lady of Lourdes pilgrimage society who have been going there for 44 years.
Friends Niamh Mervyn, Nuala Carland, Aine Treanor and Arlene Rooney didn't have far to travel from their homes in west Belfast to catch a holiday flight to Cyprus. They'd never been to Aya Napa before, but previous girlie holidays in lively resorts on the Greek islands left them under no illusions about what they might expect, though they insisted what they were really looking forward to was sleep, sunbathing and relaxing.
Football team Shaktar Soligorsk travelled to the International on Wednesday blissfully unaware that their neighbouring country Ukraine was about to be plunged into the middle of a world crisis.
The team were to beat Derry City 1-0 the following night, but on arrival at the airport Kachanovich Pavel the club's press officer was keen to dismiss reports that his side were newcomers to Northern Ireland.
“We were in Londonderry 11 years ago and beat Omagh Town 7-1 at the Brandywell in the Intertoto Cup.”
Joseph Galway, from Comber, Co Down, never thinks about Dublin airport as the starting-point for his family holidays to Cyprus.
“It's so much easier to come via Belfast International,” he says, after he and his wife, Sharon, and children Rebecca (5) and Samuel (15) checked in for their flights.