I can find 3.7 * 10^13 kg CO2 for energy yearly worldwide.
On the other hand, there are around 25 * 10^3 private jets each emitting 4.9 CO2 kg/mile, with mach 1 being 767 miles/hour, which gives 4.9 * 25 * 10^3 * 767 * 24 * 365 kg CO2 = 8.23 * 10^11 per year assuming the jets are running all the time at the speed of sound.
8.23 * 10^11 / (3.7 * 10^13) = 2.2%, with assumptions that make this a significant overestimate. Internet sources claim 0.9% from civil aviation.