Can I take booster seats on flight?

[KnickKnack]

We are flying to Portugal next week. I usually take 2 booster seats with me (just cushion part, not back). Sometimes they go in the hold, sometimes they are carried on board.

This time I am flying with Easyjet and Aerlingus.
I can't find any information on either website about car seats (they mention 5 point baby seats, but not booster seats)

Does anyone know whether I can take the seats?
for free?
check-in?
carry on board?

Help!!

aerlingus
easyjet

Good idea, however I will probably need both of them to carry a bag each onboard already.

I've used ryanaer in the past with no problems. But they are all getting so strict with baggage these days, so I'd rather be sure before I go. I will be on a bus at this side (so have to decide on car seats before I reach airport)

bump

Last year we flew to Faro with JET2 and the booster seats went in the hold and didn't count as any of the luggage entitlement. They went to a different luggage reclaim area in the airport so be warned and don't stand waiting where the bags come off like we did for ages!

i've just come back from a nice holiday, and saw two children walking onto the plane holding there booster seats, to be honest i was not on either of those carriers, but they were very relaxed about the amount of hand luggage people were taking on!

thanks guys

Can't get a straight answer from either airline, I have spoken on phone and emailed both...neither spoke/wrote english very well, they definitely did not understand my question. I've think with airlingus the seat goes into hold, but counts towards your 20kg allowance. Easyjet cannot understand the question and assume I am asking if kids are obliged to be strapped into carseat on flight.

At this stage I am just going to bring the seats and hope for the best. If need be I will squeeze their bags into my bag, and have them carry on their seats.