If you rent a car at SIXT at Copenhagen airport, you should be aware that if your flight is delayed and you will miss their opening hours you will not be able to get your car. Should you be able to reach the someone on the phone (spent 30 min in phone cue) after 18 then you can arrange to pick up the keys at an airport hotel. What they don't tell you is that you will have an additional charge of 325 DKK (currently 44 EUR). This is a nice surprise when you are sent the bill after. They will also try and get you to purchase an extra insurance again, even if you are already covered. We had asked for a toddler car seat and knew there would be an extra charge. We did not, however, think that we would have to pull one out of a pile of car seats all just heaped in a very dirty parking garage in the damp and cold, one dirtier and more broken than the next, but what do you do at 1 in the morning?