how much data are they supposed to be collecting from inside an android app that basically takes a credit card payment and displays a QR code?
Ryanair at one point at least had their margins such that every penny a passenger spends other than the ticket was profit, so they actually have less incentive to do this than some of the other carriers.
Another rather minor thing is that if you look at the source of their confirmation emails, they include a lot of reservation data in XML tags according to the schema.org specification (https://schema.org/FlightReservation). I was looking for a way to parse flight details out of confirmation emails before, and with Ryanair it is trivially easy to do because of this whereas with most other airlines you have to resort to parsing the plaintext or (awful) HTML.
Again, not a big thing but I was surprised that Ryanair seemed to be the only ones who took a standards-based approach to these emails.
EasyJet App is slop, the BA app is total shite.