You are ignoring the input v and its size, in favor of computing
v = (w*rw/(Gr*Dr))*(60/63360);
since w is a row vector (of length 100), v is going to be assigned to be a row vector.
With v being a row vector,
Fd = .5*(v*(5280/60)).^2*p*cd*cA; %lb Drag Force
is going to be a row vector, so
v_dot = Ft-Fr-Fd;
is going to be a row vector (of length 100).
However, the output from the ode function must be a column vector, never a row vector. And the size of the column vector must be the same as the size of the input v, which in this case is going to be the same size as x0 which is length 2.