Watching the test flights of the Ingenuity, small helicopter currently on Mars, somebody mentioned to me it wasn't very exciting.
Well let's see, controlling the helicopter by hand is out, unless you're happy with a 30 odd minute delay between applying a control and then observing the response. So it has to be autonomous, a fully pre-programmed flight with inputs from sensors should it require modification in real time.
As if helicopters aren't weird enough without throwing in an atmosphere just a few percent of the density of Earths.
Then there's the usual helicopter rules to be considered, (especially one that's about 180,000,000 miles away):
"If you're wing is moving faster than you are, you're in a helicopter."
"If there's nothing broken on your helicopter, don't worry, there soon will be."
"That big fan over the pilot's head is there purely to keep him cool. You don't believe me ? Just watch how he breaks into a sweat if the fan stops."
Although rule three might be less of a problem. But remember, there's no ground crew or crash services, at least as far as we know. (You can't rule out Tripod Machines I suppose. But they tend to be hostile.)