Originally Posted by
THE_Chris
On a related note, in early 2024 I booked a similar routing and this time around I was allowed seat selection, and the Transavia part of my schedule was just treated in the app as if it was any KLM flight with all the usual fiddling that can be done. I took 2A, thanks very much. Online checkin seems to be "normal" for this flight too, or at least what we are used to with KLM. So they seem to have integrated their systems more closely, starting 2024 I would reckon.
It sounds like that other flight was actually a wetlease operated by Transavia on behalf of KLM or a drylease operated by KLM on a Transavia airframe.
For the past several years, Transavia planes have been deployed on certain flights on certain routes to operate KLM flights; these can be managed in the manner you describe, as a "normal" KLM flight, although you are on a Transavia plane. It is not the same as buying a ticket that actually puts you onto a "real" Transavia flight, for which you cannot manage on the KLM app/website as if it was a KLM flight.
It was already published that Dublin, Newcastle, Copenhagen, Manchester, and Rome were to have some flights operated on HV aircraft throughout the winter timetable; I got an email a few weeks ago to inform me that one of my forthcoming Berlin flights was now to be operated by a HV plane, so they can (and do) sometimes pop up on other routes, sometimes at short notice, too.