The PAK FA is generally similar in appearance to the American F-22, though there are so many differences in detail that it is clearly an original design rather than a knock-off copy. A direct comparison with the F-22 is probably not meaningful on an unclassified basis, but Russian marketers will probably sell it as roughly equivalent in combat potential. While the F-35 is also a fifth generation stealth fighter, the low observable characteristics of this attack aircraft are said to be markedly inferior to the all-around stealth of the F-22 air supremacy fighter.