5) What happens if I don't check in online?

TUI flights
If you don't check in online for your holiday, you'll be able to do this when you get to the airport, and we'll allocate your seats from what's remaining. However, just so you know, we reserve the right to levy a charge for airport check-in.

The same service is also available for the following airlines: 

Air Europa, Albastar, ASL Airlines France, ASL Airlines Ireland, Evelop Airlines, Germania, Norwegian, Travel Service, Volotea. 
To access online check-in, please visit our Flight Extras website.

NEW You can now check-in online anytime, anywhere, even on your mobile. Mobile boarding passes are also available on selected routes. Go to the Flight Extras page to find out more.

Flights with other airlines
You'll be able to check in when you get to the airport if you're flying with Aer Lingus, Flybe or Monarch. However, if you're flying with easyJet, you'll only be able to check in online, and you'll need to pay extra to check in at the desk with Jet2.