Pilots were asked to avoid flying over Edinburgh Zoo during the breeding season so as not to disturb the animals, including giant panda Tian Tian.
A Notice To Airmen, or NoTam, was published by the Civil Aviation Authority (CAA) asking pilots not to fly in the area if possible to reduce noise from low-flying planes and helicopters.
NoTams are usually issued to alert aircraft pilots to potential hazards along a flight route such as cranes, closed runways or large public events.
The notice covering Edinburgh Zoo was in place throughout most of July, mainly to protect its breeding penguins but the likely pregnancy of Tian Tian was also a factor, the zoo said.
The giant panda was artificially inseminated on April 13 and experts at the zoo monitored Tian Tian closely in the following months.
Last week it was revealed that "the latest scientific data" suggest she is pregnant.
Zookeepers have said things are progressing as expected and they are "keeping their fingers crossed" for the arrival of a third panda at the end of this month.
Tian Tian's hormone and protein levels are being checked regularly but it will not be known for certain if she is pregnant until she gives birth.
The panda was successfully inseminated last year but lost her cub at late term, something the zoo is wary of happening again.
A spokeswoman for the zoo confirmed that a NoTam had been in place.
A CAA spokesman said: "Following a request from Edinburgh Zoo through the air traffic control unit at Edinburgh Airport, we issued a NoTam on July 11 requesting pilots to not fly within a one-mile radius of the zoo or below 1,900 feet above sea level.
"The NoTam was advisory so if necessary, pilots could still fly through this area providing they complied with the rules of the air.
"The NoTam expired on July 31 and there are no plans to issue any similar advice to pilots operating in the area."