A commercial airliner will not support sustained coordinated flight with a 90 degree roll attitude. This is because the vertical lift at 90 degrees is greater than the weight (and therefore lift needed) to support the aircraft.

In general, aircraft with can perform sustained flight in a 90 degree roll attitude will have either some way of creating lift in that direction or will use thrust vectoring or both. Commercial airliners do not have these attributes. Actually very few airplanes do.

So in the case of a commercial airliner, in a 90 degree roll, one can expect that it will be "falling" towards the ground, with increasing velocity as it accelerates. This is because it generates insufficient vertical lift in that flight attitude.

A commercial airliner will not support sustained coordinated flight with a 90 degree roll attitude. This is because the vertical lift at 90 degrees is less than the aircraft's weight (and, therefore, the lift needed to support the aircraft).

In general, aircraft with can perform sustained flight in a 90 degree roll attitude will have either some way of creating lift in that direction or will use thrust vectoring or both. Commercial airliners do not have these attributes. Actually very few airplanes do.

So in the case of a commercial airliner, in a 90 degree roll, one can expect that it will be "falling" towards the ground, with increasing velocity as it accelerates. This is because it generates insufficient vertical lift in that flight attitude.