Airport chiefs in Belfast say they hope plans to grow passenger numbers will finally get the go-ahead following a public inquiry.
The four-day inquiry, which opens today, will scrutinise controversial proposals to scrap the "seats for sale" restriction at the George Best Belfast City Airport.
Residents living near the flight path oppose any changes to the current planning agreement, fearing "intolerable" noise levels from an increased number of flights. But airport bosses insist lifting the limit would boost the economy, create jobs and attract new airlines.
Brian Ambrose, chief executive of George Best Belfast City Airport, said: "We look forward to the public inquiry and the removal of an outdated constraint on our operations."
Currently the airport operates under the restriction of selling two million departing seats a year.
The battle for its removal has been ongoing for over a decade and has resulted in a number of legal challenges.
Liz Fawcett, chairwoman of the Belfast City Airport Watch steering group, said up to 18,000 residents across south and east Belfast as well as North Down could be adversely affected if the planning agreement was altered.
She said: "We have robust evidence that many residents and their children already suffer disrupted sleep, higher stress and poorer quality of life, due to existing levels of aircraft noise.
"It's quite intolerable for the airport to heap further misery on residents in the pursuit of higher profits when we already have an international airport sitting in a green field site with spare capacity just up the road."
The number of flights in and out of the City Airport is capped at 48,000 a year with operating hours between 6.30am and 9.30pm and penalties for late flights.
Removing the restriction would not mean an increase in the number or size of aircraft and new measures have been put in place to monitor and tackle noise pollution, it has been claimed.
Mr Ambrose added: "No larger planes will use the runway than currently do so.
"Those living in proximity to the airport will continue to be protected from noise with no night time flights and no cargo planes.
"If the seats for sale restriction is removed, the airport will adhere to noise restrictions as imposed by the Department of the Environment."
Last year 2.5 million passengers were carried on 37,226 flights from Belfast City Airport.
The public inquiry, ordered by former environment minister Alex Attwood in 2011, is being held by the Planning Appeals Commission at Park House in Belfast city centre.
It is expected to hear evidence from a wide range of parties including the airport officials, residents' representatives and aircraft noise experts.
C lea Driscoll, from Kinneg ar, Co Down, said her family life had been severely disrupted by noisy aircraft.
Mrs Driscoll said: " When we first moved here, more than 10 years ago, the planes weren't such an issue.
"But things soon got worse and, when our sons were small, the noise really disrupted their sleep. Now, we've swapped bedrooms with them, and it's my husband and me who get woken up.
"But what really irks us is the fact that you have to keep the windows and doors shut if you don't want to be blasted with noise - that's very frustrating in the summer especially."
Elizabeth Bennett, 74, from Sydenham in east Belfast, said her health had also been affected.
She said: "Although I'm retired, there's no chance of a lie-in because the planes start at 6.30 in the morning.
"You can't escape from the constant drone of the planes, my health has definitely suffered and I find it very hard to relax properly in my own home."