I second this suggestion, with some caveats.
I thought there could be a place to improve QoL. Currently, when you arrive at the mission site, you can choose to patrol over it, in order to wait for the daylight. But when the time comes, the player goes to the craft actions state, then hit "Select new target" and then selects the site that is under the craft. How do you think, does it worth another making another button to avoid selecting destination?
For instance, when we choose to patrol over a mission site, we can make a link between the craft and the mission site. We break this link on 1) new target, but current site was selected, 2) low fuel.
Thus, when we select the craft actions, we could create a new button, that would tell the craft to deploy mission. That would save us a few pointless mouse clicks.
This link would allow us to make another feature - alert the player, that mission site is about to despawn and he or she has to choose return to base or deploy now, as we can't wait any longer. Ofc, both should be hidden under ruleset toggle or option.
I wouldn't tell the player when the landing is about to despawn, that's part of the intended gameplay to never know when the landing site will despawn.
It would be nice to have an option to wait until daylight to start the mission. I think this could be accomplished in a few different ways that would minimize the change and feel to the original X-Com. When the window pops up asking to Begin Mission? [YES] [NO]:
1.) There could be smaller text just below the yes/no with the following "Wait: Patrol Until: [ ] Dawn, [ ] Daytime, or
This way you can choose at each mission the option when to start the mission, and if the landing despawns the you're out of luck. Start Now would be the default, or you could have an advanced OXCE option to "remember last selected patrol wait setting when beginning missions"
2.) There could be a button just below the yes/no that says [Patrol Until Dawn]. If the player chooses that option then when dawn comes the start mission window pops back up. This would also allow to accelerate the globe clock to that event and also not miss that event either.
3.) Have an OXCE advanced option that is "Cancel mission start, craft patrols instead of base return"
I use Starving Poets "OXCE - Day Night Indicator" mod so that when the craft arrives at the mission site I don't have to always default to cancel mission just to check if it's day or night time before starting the mission. The problem I run into is when it's night and I want the craft to patrol until daytime, I place the craft into patrol mode. I can speed up the globe clock but sometimes, especially when I have multiple crafts out, I can speed up the clock to much or I miss starting the mission.
I would suggest either options 1 or 2 above that way you wouldn't miss a mission start needing at daytime, the 3rd options it would still be easy to forget about a patrolling craft when there's a lot of crafts our, accelerating the globe timer, etc.
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, humanoid aliens like floaters, sectoids, mutons use BAI, and snakemen and some other aliens use VAI or somewhere in between with different flags so that you get varied behaviors per alien race. 
:'(