People opposed to the expansion of Lydd Airport in Kent have been canvassing support by showing residents how loud passenger planes can be.
Protesters played recordings of jet aircraft to villagers
Campaigners took recordings of jet noise to villages on the Romney Marsh to highlight their plight.
Managers want Lydd Airport enlarged to cater for jet aircraft, carrying up to two million passengers a year by 2011.
The airport said trial flights had been carried out, with only eight "comments" received from the public.
Malcolm Dyer, from Keep the Marsh Special, said: "We know that large jet aircraft are noisy.
"But to be precise in terms of the exact decibels to be heard at one point or another is something only a scientist can do under controlled conditions."
But Zak Deir, managing director of Lydd Airport, said: "It is a pathetic way of measuring noise and showing the public what a jet engine would sound like."
In September, airport bosses arranged for a 37-seater twin-engine passenger jet to fly along flight paths that would be used for commercial airlines using Lydd.
Public reaction to the exercise was monitored and eight people phoned the airport enquiring about the noise.
Managers said they were "reassured" by the results.
Protesters claim expansion of the airport will harm the environment, quality of life for local residents and the area's tourism trade, all of which the airport denies.