I'm selling my spark to upgrade it but i cant choose for wich drone mavic pro or the mavic air .

Mavic pro have a better connection i guess not wifi but its way bigger .
Mavic air is smaller but same connection as the spark ..

Maybe you people can help me to choose .

This question has been answered many times before. Search "Mavic Air vs Mavic Pro" on this forum or Youtube and you will see plenty of comparisons which will probably guide you on your way to buy a new drone. I'm sure you'll be happy whichever model you choose!

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CONSUMER DRONES COMPARISON

I say go for the pro!!!
I have a spark since July and now a Mavic Pro since a couple of weeks ago.
Pro is much better than spark in everything except for taking panoramas
The connection is amazing and rock solid, I did 5km one way today with perfect signal all the time, I only turned back because of the RTH battery warning, otherwise I could continue no problem!
The air has better camera than the pro, but the pro has better everything else!!!

Fly safely and enjoy all
Alex

The decision had to be yours ofcourse. But to know which one you should get you should think of the pro's and con's of each. And you have to think of what you are going to do with it.
Personally, I have the pro, and a friend the air, I flew with his, and he with mine, and we both wanted our own drone back after a few flights. So it is really personal of what you would like