The engines of modern commercial aircrafts are generating thrust to more than 80% not with the exhaust jet. The turbine in which the fuel is burned, is used mainly to drive the so called fan (blower). The fan is in principle nothing more than a propeller in a tube housing. I think, that hardly no one will claim that the vacuum in front of the fan blades generates the thrust, but clearly the air masses that are pressed backwards out of the thrust nozzles. This also explains why normal aircrafts and in particular helicopters are limited in altitude. The air is getting thinner with increasing altitude. The air mass that is necessary to "carry" an aircraft is no longer sufficient, while the force of gravity (the weight) remains the same. This can only be compensated by a higher airspeed.