For location based email sending better use ifttt.com.

The delay send feature should be exactly what the MacOS version is. Have several delay options, have the email go to the drafts folder until it actually sends, and have the undo option pop up on the screen during the time you have the delay set.

Having email queue up in them send folder until you have connectivity again would be very nice though.

Would love to have this option!
New email app from easilydo have it and it works like magic!
Can you please include it?
With an option of picking the time for delay.

Undo a deletion or spam

This sounds great!

I work in an airline industry and work on an e-mail inflight and would love it if it would automatically send when I land and not having to go into draft and send it.

Scheduled mail sending.

Yes!!! With options for how much time you have!