We travel quite often.... recommend car seat bag for travel off amazon and or those big laundry bags. We fly with Easyjet and last time managed to blag 70kg of luggage without question on as a travel cot and a car seat.... in reality, we had chucked in 2 car seats, a pram, a travel cot, nappies and formula etc. We live abroad and so buy secondhand when we visit the UK to bring it back here where everything costs a small fortune!
We packed the car seat in a large hold-all and surrounded it with nappies and our beach towels etc Just checked it like normal luggage and no one checked
Do a click and collect at boots for nappies and formula if u formula feed. Make sure when you do the boots click and collect it click after security xx