...there was quite a lot of guessing for me. Thanks anyway for the effort...

The most difficult of the flying object puzzles. Four linked skydivers, with their heads 2 by 2 squares
SPOILER-heads r5-6 c12-13, r9-10 c9-10, r11-12 c15-16, r14-15 c13-14.

Thank you for the hints, Margpheb! I don't think I ever would have solved it without them.
Very cool image! Thank you, Hell-Seher!

Seemed logical to me (no hints needed). Thanks.

Thank you for the hints Margpheb. I was really finding this one difficult but managed to complete it with your hints. Very nice Hell-Seher but difficult, Thank you.

Very clever! Interesting image. I found it 100% logical..

Don't think I guessed but may have filled in squares that became 'obvious' as I always do.

Whew! That took a little while. Fully logical, able to solve without hints. Thank you!

Logical.

Merci l'aide