If we really had to...
It takes not far short of 10 years from the idea of a new airliner to operational capability, decades for military aircraft and many years even for piston singles. Certification, testing etc. etc. etc.
Imagine its war. With the martians (or some equally menacing foe). Money is no object. There is internation collaboration. Could we do the following within 12 months if we really had to? No time for certification, extended life cycles or perfect safety - its just got to be done.
Project 1. An aircraft is required to lift a payload of 400,000kg in the form of 200 1metre cubed boxes each weighing 2000kg over a range of 5000 nm, unload within 24 hours, return empty and complete the same mission 10 times.
Project 2. An interceptor is required to take off, climb to FL500, cruise at Mach 3.5 for 1000 nm and return to base (not necessarily where it took off. Again, 10 missions required.
Project 3. A payload of 16 people must be raised to FL500 in a pressurised environment, hover (by any means) in a geostationary position for 30 minutes and return safely. 10 missions required.
Ground Rules. Existing infrastructure to be used. All aircraft to be operated by a minimum of 2 crew whose safety will be an important, but not paramount, consideration. Assume limitless funding, international co-operation and some red hot project managers.
The planet's future depends on it.
Could we do it?