You can fake the jet blast reasonably well, try modeling the blast as a mesh, and set its material to a null-scatter mix and putting a bright light at the engine itself. Looks something like this: http://www.luxrender.net/wiki/LuxRender ... er#Example
It really should be an emitting medium, but Lux doesn't support those yet.
As for the heat shimmer....as best as I can figure out from googling, the shimmer comes from the heat changing the IOR of the air in the exhaust. Which would require heterogeneous mediums, which is also not supported yet. Not sure there is any way you could fake this one.