Would turbulence created by two jumbos less than 100ft apart cause both of them to crash?
The probability of two jets surviving such a close encounter are extremely remote.

Setting aside the fact that it is difficult to imagine two aircraft flying in the same altitude in opposite directions (commercial aircraft are separated by 3 miles laterally and 1000 ft. vertically) ,if the scenario unfolds as in the movie and the horizontal separation between the aircraft on approach is as shown, the pilots would not have time to react and take the necessary evasive actions.

Assuming that the jets are cruising towards each other at 900 kmph, the combined speed is around 1800 kmph, or half a kilometer per second.

If the TCAS is not working and the aircraft come within five km (the distance in the video is considerably lower, less than a km) of each other, the pilots have less than 10 seconds to get out of each other's way. 

The civil aircrafts are not designed for such rapid roll rates. The inertia of the aircraft (especially the 747) will limit it.

Another thing to note is that the modern flight control systems will not allow airline pilots to carry the maneuvers shown in the flight. The pilot can override the Flight control Computer.However,in this case, they would not have time to react.

If by some miracle the aircrafts cross each other, they will fly right into the other aircraft's wake turbulence, which will have disastrous consequences, especially for the smaller aircraft.


Sources: airpower.maxwell.af

In case of small aircraft flying behind a heavy jet, FAA regulations require a minimum separation of 5 miles, lesser than which the effect of the wake turbulence (wingtip vortices) can have serious consequences.


Source: Aeronautical Information Manual

FAA conducted a test on the effects of wake turbulence by flying a 737 behind a 727, which shows the loss of control associated with flying in the wake of another aircraft.

Once (if) the aircraft pass each other, they should be brought to level flight as quickly as possible (whether it is possible or not is another question) to prevent stall. In this critical juncture, if the aircraft wings encounter wake turbulence, the control of the aircraft will be loss, resulting in stall. 

Finally, in case two aircraft do approach each other in the same altitude in opposite directions, there are laid down procedures to follow. None of them involve the stunt shown in the movie.

When two aircraft are flying head on, each must move to their right.


Source: planefinder.net

If two aircraft are at the same height and on converging courses, the aircraft with the other on its starboard side has to give way.


Source: planefinder.net