My home is on the approach path to a low traffic volume regional airport. The Army and Marines use this airport for training periodically. Once a week Ospreys come in for touch and go's. I can hear these things coming for 3-4 minutes before they fly over. Very distinctive and unique sound. At night during humid weather their rotors generate St. Elmo's Fire at the tips so that the rotors are outlined by bright green circles of plasma. I'm not sure I'd want to ride into combat on these things if they announce their presence in such a manner. Seems like every AAA emplacement within 10 miles would know you are there without needing radar. There sure isn't anything stealthy about them. Blackhawks and Chinooks are far less noticeable.

But the V-22 is far faster getting in & out of a hostel area.