It's a myth that if you bring a car seat, you have to keep your children in it the whole time. My kids hated their car seats but it really made flying easier. The big issue is when the fall asleep. You have somewhere safe to put them down. You can get a drink or go to the lav without worry.
Also, holding a toddler for take-off and landing can be a challenge when alone. Parents have been "off loaded" because they couldn't control their child who wouldn't stay in their laps for take-off. Being in their car seats meant that even if they weren't happy, I could spend my energies comforting them while we were both strapped in, not just keeping her in place.
So a car seat is the best solution and claiming that the child doesn't like sitting in it for 12 hours is isn't a valid reason for not using one. NO child on the planet will sit in a car seat nonstop for 12 hours. That's not reasonable and not required.
The reason the bed on the floor doesn't work is that if there is unexpected turbulence, your baby's head is going to slam down on the floor. The poster who used a Moses basket was very, very lucky.
The only airline I know of whose bassinets will fit a 14 month old is Lufthansa.