I used an IGBT transistor switch at my last company to drive an air coil for an electromagnetic detector (similar to a metal detector). To test the circuit, I had it pulsing an old Mopar coil, with the spark jumping 2" in open air. When it hadn't failed all weekend, I decided it would work fine (it did). However, it is easy to spark at 1 atm pressure, and even easier in a vacuum where sparks readily jump many meters. In an automotive engine, the spark must work at 200 psi cylinder pressure, which is much harder and why a 0.060" gap is about the limit for most ignitions.