I take it you arn't familiar with aircraft history. Have you ever heard of Russian pilots secretly flying Mig-15's in Korea? Even though there was a small handfull of them (26) they acheived 241 kills, although the UN only gives them credit for 108 kills. Moreover, this group of pilots acheived more than half of all F-86 kills.
Something a little bit more up to date would be comparing something like the F-4 and Mig-21, both are of the same time period. The F-4 certainly has the better record than the Mig-21 but that is largely in part due to US and Isareli pilots which are exellent pilots. Likewise, the Mig-21 pilots were average to poor at best, (Vietnamese pilots were average, Arab pilots were poor). The record stands something to the tune of 1.68:1 F-4 to Mig-21 kills. Or 89 F-4's lost compared to 150 Mig-21's lost.
Pakistani pilots also shot down a number of Israeli aircraft while flying the Mig-21, all the while the Arabs struggled against the Israelis while using the same aircraft as Pakistani pilots, so pilots have a lot to due with the out come of kill ratios or combat records.
