Are you a heavy sleeper or a light sleeper? Some people once they fall asleep, they do it so seriously that they could literally be carried to a different location and hear none of it. Others will be asleep but still answer when you call them, or be aware of things going on around them.
Some people will fall asleep easily too. All they need to do is close their eyes. It doesn't matter whether they are in a moving car, on air, or in an uncomfortable environment that could be noisy, too hot, too cold, or with not enough space to stretch out for comfort. They will still have their beauty sleep regardless.
Other people need a lot to fall asleep. If a place is not comfortable enough, quiet, with the right temperatures, and dark, then they could be unable to fall asleep. Some are even unable to sleep in unfamiliar locations or without a certain pillow. Well, whichever category you fit in, here are asleep quotes that you will certainly relate to.