It's really not clear what your if statements are meant to do since you wrote some calculations that are not assigned to anything. In any case, the efficient way to do whatever you want to do is not to use if or loops:
Roll = 0:5:180;
Pitch = 0:5:90;
[Roll, Pitch] = ndgrid(Roll, Pitch); %cartesian product of the 2 sets
%taking a guess at what you want to do. Your conditions don't make sense
Result = zeros(size(Roll));
Result = 180 ./ Roll + 90 ./ Pitch / 2; %generic case
Result(Roll < 40) = 180 ./ Roll(Roll < 40); %other condition
Result(Pitch < 40) = 90 ./ Roll(Pitch < 40); %other condition
surf(Roll, Pitch, Result);
