Even if the F-22 or F-35 may be outdated. I'm sure the US government is working on new technology and airplanes that we've never seen. It is highly possible, as was the case for the F-117 Nighthawk and several other programs at Area-51.
How Area 51 Hid Secret Craft
There is even the X-37B, which is being operated by the Air Force, that no one really knows what it is doing in space. There are plenty of theories, but no facts.