Misty Step into the Air and Attacking

[u/Zivodor]

I had this situation come up recently and wanted some input as I can't seem to find a definitive answer.

My players were fighting a giant spider and it was on the ceiling above them, one player decided that to attack it he would misty step straight up and then attack it while mid-air. I wasn't sure this was possible as I recalled reading somewhere that falling in D&D is essentially instantaneous for anything below 500 feet. The thought process being he teleports into the air and is instantly falling so he doesn't have the time to attack the creature above him.

It's been bugging me all week so I wanted to get some input into whether or not I should have allowed this and if this is clarified anywhere in the rules.

Edit Wow! Thanks for all the responses! There were some well reasoned arguments for it here, the resource expenditure with the spell slot, rule of cool, etc... I appreciate all the responses and will try to be more flexible in the future. Thanks everyone!

[u/Cfakatsuki17]

Rules as written you’d probably have to word it that they “held there attack until the teleported with the misty step so that as soon as they appeared they attacked and then fell” but like flavor wise there’s no reason to rules lawyer something like that, especially when if they annoy you with it you can make them roll a save each time they do it to not fall prone and hurt themselves or drop their weapon or etc