In the Jul 09 issue of National Defense magazine, Col Eric Mathewson, director of the Air Force's Unmanned Aerial Systems Task Force discusses some of the things UAV's will never do: "There's no way you can replace an F-35 or F-22 or something like that... No way."
In related news, "Lt. Gen. Dave Deptula, the Air Staff's head of intelligence, surveillance, and reconnaissance, said it is not unrealistic to imagine an unmanned aerial vehicle as successor to fifth-generation fighters-the F-22 and yet-to-field F-35-in our national military strategy, however he added that UAVs still require some technology maturation before they would be ready to assume that mantle. (AF Magazine Daily Report, 27 Jul 09 )
Which reminds me of a quote I heard somewhere, that went something like this: When the esteemed and aged expert says a thing can be done, he is most certainly right. When he says it cannot be done, he is most certainly wrong. (can anyone help with that reference?)