you really need to use the formula for kinetic energy rather than F=MA
KE = 1/2 x mass x Velocity Squared.
So with 2 identical aircraft with the same drag and at the same velocity the aircraft with the higher mass will have higher kinetic energy.
Or the same aircraft both at the same mass with one travelling faster than the other, the faster one will have higher kinetic energy and thus take longer to slow down as well, But bear in mind that drag is also squared with velocity so the faster aircraft will have higher drag until it slows down to the same speed as the other one was at.
so we can't use the F=MA formula as it doesn't allow us to take account of the velocity of the aircraft at the point of forward thrust being replaced with momentum / inertia.
With 2 falling objects you initially ignore mass as the both accelerate towards the ground at the same rate of 1G, until terminal velocity is reached then if the objects have different mass as the drag of each object equals the mass of the object acceleration will become zero and terminal velocity is achieved.
so for a faster terminal velocity with the same drag, you need a heavier aircraft.
water sufficiently muddy i hope.
GB