yeah but ya cant exactly just pull over and see whats wrong either!
Sounds like you've been subjected to a lot of hype, and/or misinformation about flying and airplanes. There's a lot of that. The media would rather scare you than inform you. So, they often make "errors" in their reports.
1. You can land at any airport, or open field, etc., if necessary.
2. Most aircraft engines have two plugs per cylinder.
I've only had an aircraft foul plugs once. It was a rental training craft, that likely had many students forget to lean the engine properly. Even then, the engine still ran, albeit with less than max power. With proper leaning and at cruise power setting, the plugs eventually cleared themselves, max power returned, and I flew on another 200-300 miles without further incident. ...But I kept it lean even while taxiing, whereas the book says to operate at full rich. Experienced pilots know better, I later found out.
Anyway, routine is to do a run up check before takeoff to see if the engine will make proper RPM. If it doesn't or the engine is misfiring on cylinders, you don't take off and return to your parking place or repair garage.
Pilots take far less risks than 90% of the driving populace.
I had a 360 CI flat four Lycoming that snapped an exhaust valve shortly after take off. Far more severe than a single fouled plug. The engine made a lot of noise, before chucking the valve tulip out the exhaust port, into the muffler. The plane still flew, even if shaking lot. Flew it back to the airport I took off from, and landed normally. I changed pants. And then, jumped into another plane for the scheduled flight.
There are old pilots and there are bold pilots. But, there are no old, bold pilots.
May you find the comfort you seek.
Cheers,
