Using SSIS, If I have a 50 byte char input field (flat file) and want to put it out to a 70 byte char output field (Flat file), I should be able to see the output field with 50 bytes of data with trailing spaces of 20 bytes but I don't. I know I can pad the field with additional spaces but I sure hoped that without padding it should have put the trailing spaces due to the length of the output field.

Question.
SS38
Have you tried adding a final field that has length 1 but nothing output to it. Maybe that will solve the problem.
Flat file parsing is a complex beast and many different systems handle your situation differently. As mentioned previously working with Biztalk on th esame issue you either find it works the way you want it or it doesn't, some you win some you loose and its a game of two halves :)