UPDATED Southampton Airport says there’s a “lot of conflicting information circulating” about its proposed expansion plans, and any impact of noise, and will be organising public information sessions so people can raise questions and discuss concerns.

In publicity the airport lists various measures it says it’s taking to minimise noise, and adds: “We are particularly concerned that residents are being told that jet aircraft are 63% noisier than turboprop aircraft. We do not know where this statistic has come from and would question its reliability.”

You can read information about noise, provided by the airport in their own words, from this link (pdf). 

Dates, locations and the format for the airport’s public information open evenings haven’t yet been announced

Update 27/8/19: A 63% figure is referred to on the Marlhill Copse website [scroll].

Responding on noise, Gareth Narbed, who has campaigned against tree felling at Marlhill Copse, said:

"http://www.airportwatch.org.uk/the-problems/#NATSnoisedata ...quotes figures provided by NATS. Table 1 lists the Airbus A320 and the Boeing 737 (the large jets that use Southampton airport) as  "125-180 single aisle 2 engined jets".