Just to add my little bit.
As others have mentioned, grades aren't everything. My GCSE's weren't startling, my A levels thoroughly average, I did get a degree but not an essential qualification. I now do what you aspire to do (ok maybe not on the aircraft of your dreams!) so all is not lost.
My point is that grades are not everything. If it's what you want to do then go with it and you never know. You may well have a lot more to offer than simple academic ability.
BV
