Flybe have too many aircraft flying unprofitable routes. Provided AF/KL play ball, they will regain aircraft availability to place elsewhere on their network. Flybe can take over the routes and slots that match the capacity required. EG replace AF/KL routes flown by the ATR/E170/190 of KLC and Hop! with BE Q400/170/195, freeing up AF/KL to open new routes elsewhere through Europe. AF/KL can also save on nightstopping aircraft and crews out of base in the UK with BE taking on the early flights.
AF/KL mainline continue to fly with their own metal where Airbus & Boeing size are required.
Not sure how that would play out with AF/KL unions however...
Well let me rephrase that.
If I book an Air France or KLM ticket in an expectation of flying on their own metal and service levels which have been well supported from the UK regions since the '80s, I don't really want to fly on an old second hand Q400 with flybe. Nor will either set of union be happy to see their own profitable flying being given away to a basket case British airline that couldn't make money....well frankly at all. That's not to say Air France might not try, look at the farce of JOON, another example of an outfit not being fit for the market they were operating in. Am not sure anyone benefits from swapping a new KLM ER7 for a Q400, and let's be honest, flybe just cannot ever make money with jets. They negotiated the worst leasing agreement in known history on the Embraers that's been an albatross round their necks ever since. Not sure why KLM or AF want to swap money making routes to redeploy their assets on new routes, there's gotta be a balance IMHO.
Personally given how Air France and KLM are an uneasy marriage, I am baffled as to how Virgin really adds anything. So they can codeshare between two points VS don't even fly to, wow! It would be different if there was a decent feed from CDG or AMS onto VS long haul at MAN, but is that something the big two are willing to do?