Stoned,
The Falklands Mod people have done a very good Skyhawk in USS Enterprise (I think) colours. Also on ofp.gamezone.cz, there are a number of marks of MiG-21, but I don't know if any of them are in North Vietnamese colours.
I've experimented a bit with fast jets and due to the map sizes you get better results with slower aircraft - maybe a MiG15/17 would be a better choice as a 21 at full speed could cross Nogova in under 20 seconds (Mach 2 = about 660 m/s, Nogova=about 10km across).
For what it's worth, I think this topic is appropriate for the editing forum because choosing (as opposed to making) a good addon is often crucial to building a mission. In the case of historical missions, this is especially true. Anyone agree/disagree?
:gunman: Remember, short, controlled bursts...
Ade