Problem for the jets is they are very vulnerable at take off and landing; it was how the Allies combated them OTL.
and the poor quality material used in making the engines and you need a skilled pilot to be careful with the engines tokeep them working.
Developing the new power unit was difficult enough, but German engineers faced a further problem. Owing to the Allied blockade; the hardening elements necessary for effective high-temperature-resistant steel alloys-in particular, chromium and nickel-were in short supply. Only limited quantities could be spared for the jet-engine program, so those who worked on the new propulsion system had to make the best of what was available. For the Jumo 004 engine that powered the Me 262, Junkers engineers used some substitute materials that were not up to the job.
For example, the combustion chambers were made of mild steel and coated with baked-on aluminum to prevent them from oxidizing. When the engine was running, these combustion chambers slowly buckled out of shape. The turbine blades were made of a steel-based alloy that contained some nickel and chromium. That material was insufficiently resilient, however, when the engine was running, the centrifugal forces used the blades to elongate, or "creep."
Limited by combustion chamber buckling and turbine blade"creep," the running life of pre production Jumo 004s rarely reached 10 hours. Throughout a flight, careful throttle handling was vital to avoid having an engine flame-out or overheat. At altitudes of above 13,000 feet, the engine became increasingly temperamental, and if it suffered a flameout, the pilot had to descend below that altitude before he attempted a relight. In its early form, the Jumo 004 had too many weaknesses to allow mass-production.
After much hard work to improve matters, late in June 1944, the Jumo 0048-4 emerged with a running life of 25 hours. That still wasn't impressive, and certain reliability problems remained, but the Luftwaffe couldn't afford to wait any longer. The design of the Jumo 0048-4 was "frozen" and the unit was put into mass production. During Sept '44, Jumo 004B-4 production reached significant levels, and that month, the Luftwaffe took delivery of 90 Me 262s.
http://www.fiddlersgreen.net/models/aircraft/Messerschmitt-Me262.html