That was actually true prior to the current generation of video-based targeting in air-to-air and ground-to-air missiles.
Hard to hide from a computer processing your multi-spectrum video image, though.
Likewise, if all of your airfields are being overflown by UCAV's that can stay over the target for 36 hours at a time, landings and take-offs become a bit problematic regardless of your airframe.
From what I understand, the video-trackers still aren't reliable enough to put into production and have a nasty habit of homing back on other "friendly" aircraft.