The only notable exclusivity that GLA has over EDI is the Emirates A380, but there'll be less draw for that now that Emirates have returned to EDI, now with the A350. I think it's more that these services are likely run by McGill's Inchinnan depot (a stone's throw from GLA), so having them in service - even a couple of passengers - reduces the cost of dead running.
Someone may be able to advise otherwise but I don't think it's just Inchinnan trips which are serving the Airport. Yes it's being used sometimes to reduce dead mileage the but some other trips look to be normally extended and evening journeys were retimed to take into account some of the extensions. I believe there to also be some instances of buses on the 091 still running dead from the depot to Glasgow (06:15/07:15 from Glasgow and 22:00 from Aberdeen).
While Glasgow Airport may not have much exclusivity, there are 8 million passengers per year (according to latest Civil Aviation Authority figures) so people are using the airport. Exclusive routes isn't always why people choose to use certain airports, sometimes people prefer the service from a certain airport, or the fares may be cheaper or one of many other reasons. The Airport can be served at a seemingly minimal cost and given the dismal public transport links currently from the airport, perhaps this will help the Airport grow and give Flix some passengers and give them a USP on the route. All at no cost to existing passengers (which Edinburgh would be).
I suspect you’re right about the Inchinnnan depot being a big part of the logic here. Is the 090 Glasgow - Edinburgh services run out of Livingston rather than Inchinnan? I suppose that would explain it if so.
I believe it's shared between Inchinnan and Livingston and this is something that they should do. Same for the 093 Inverness service, 2 buses each day on that seem to be ran by Inchinnan and run dead to/from but maybe the 091 is just a small trial to see if it's worthwhile.
There's no real difference compared to what the Megabus services were using towards the end, in fact a few of the Flixbus operators were running Megabus services before the network shut down. I don't recall hearing of any issues with the Cardiff stop from drivers.
Megabus were still using interdeckers which of course had front loading for wheelchair users and the lockers lifted up. I know Megabus drivers that I have spoken to have said about issues with coaches that Watts were using at one point because the lockers were flaps rather than rising lockers (if that makes sense), so they had to park in the middle of the stand else the locker wouldnt hit the bus shelter and not open.
Megabus I think also had less buses per day than Flix. Flix has 58 services per day either departing or terminating at the stop. It's a lot and it's set to grow slightly in June as well (And maybe grow more depending on any currently unannounced partnerships or enhancements)
