Evidence
CAA origin and destination data it shows the following:
PMI 400,000 air passengers from BOH 90 min catchment (3.9m people) annually leaking - i.e not flying from BOH but using others such as BRS, SOU, LGW, LHR, LTN, STN etc
ALC is around 250,000 per year
AGP is around 350,000 per year
FAO is around 150,000 per year
We know people drive for 90 mins for Ryanair fares.
Some big volumes for other markets too. Data is on anna.aero under routes shop and Bournemouth airport.
Now of course, it would be impossible to get all of those pax, but extra frequency would stimulate new travellers at low fares.