If you're looking for a way to aggravate a flight attendant, put your luggage in the overhead bin lengthwise.
But if you want to be a good passenger, do you know the correct way to put your luggage in the overhead bin on an plane?
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As well as putting your case in widthways, remember to put the wheels first. Apart from anything, this makes it easier to grab the bag when you're getting off.
Jackets and coats go on top of the bag. Smaller bags go under the seat.
And If the bin above your seat is full, it's okay to use one a few rows back. What's not okay is to take another passenger's bag out of an overhead bin to make room for your own...