There is a car seat air approval for Europe, it's called TUV approval.
I think the only current Group 1 seat which has this is Nachfolger Hy5 which is an inflatable rear facing seat. You also have several infant carrier type seats which have the TUV approval, some larger ones of which would fit a 22mo unless they are very big for their age.
However you also have to look at the airline's policy and a lot of them say no rear facing seats to be used on board, only forward facing. There are some older models in Group 1 (forward facing) which had TUV approval but they are all now discontinued:
Britax-Romer Eclipse
Britax-Romer Prince
Maxi Cosi Priori (I think? Unsure about this one)
Kiddy Infinity Pro
Kiddy Discovery Pro
Kiddy Guardian Pro
Kiddy Phoenixfix Pro
Diono Radian 5
You could try to get one of these seats second hand - the Eclipse is the easiest to find, as it used to be really popular/sold everywhere as a second or travel seat plus it was the most recent one to be discontinued.
The other thing with airline policy is that a lot of the time if you look at it they don't actually require the TUV approval, they just ask for ECE R44 approval, which is the (old) approval for use in cars plus for the seat to fit within certain dimensions. But the problem here is that they also say it has to be able to be fitted with lap belt, and there are no car seats currently on sale that can be fitted with lap belt because the safety regulations have tightened up, and the amount of movement you get with a lap belt fitting isn't permissible any more. The policy is also often really out of date - it's common for them to cite R44.03 (which was superceded by R44.04 in 2008 and R129 in 2018) and there aren't any R44.03 seats on the market any more, even though they are still legal to use. Even most R44.04 seats are now being discontinued as they aren't being sold in the EU any more.
Because lap belt approval doesn't work any more for road use and TUV approval doesn't make much, if any, difference to car seat sales you find car seat manufacturers don't bother with it.
So if you really want to push your luck/bend the meaning of the policy but get through on a technicality, you can take any belt fitted Group 0/1 seat which has a forward facing option if you can physically fit it with a lap belt - Joie Tilt, Joie Steadi, Graco Extend are seats I've seen people use in this way successfully. (Also Britax Two Way Elite but that's discontinued too).