Jet2, one of the cheapest flight operators BEFORE you add all the non-quoted for items.
Just did a Newcastle to Dalaman price check, a very reasonable £463 for a family of four becomes £749 when you add the taxes, £12 each for airport check in!!! and should you want to take luggage with you, that's £22 a suitcase each.
Should you choose to use the alternative, online check in,you don't pay for "airport check in" at £12 each, you pay £6 each instead. Your initial £463 becomes £725.