Hire a lens for airshow days for four thirds DMC-G3 camera?

[SwissJonese]

I have a Panasonic DMC-G3 Micro Four Thirds camera which I want to take some in-air shots at a couple of airshows over the next few weeks.

I can hire lenses from HireACamera.com but not sure which one would be best, can anyone recommend one?
Lumix G X Vario PZ 45-175mm f/4.0-5.6 ASPH Power O.I.S.
Lumix G Vario 100-300mm f/4-5.6 Mega O.I.S.

[Golaboots]

Think the G3 is pretty much the same in the Autofocus department as my wife's GX1.
If it is then AF tracking is best described as 'not quite up to DSLR standards', this could be the lens as much as the camera but it is a drawback of mirrorless cameras of that age.

Not sure which m4/3 telephotos are the fastest for AF but would recommend stopping down a bit to improve the odds of getting anything in focus.