There was at least one other way, at least in the RCAF. My uncle entered with a direct commission in the late 30s. He applied for pilot training but was refused as he had a minor visual defect. He rose to SqL in the supply branch. Later the powers that be lowered the bar and he qualified but was refused on the ground that he was too valuable in the supply branch. He then took 2 weeks leave and returned with a PPL. He was then accepted for training but had to accept a reduction in rank to PPO (Provisional Pilot Officer). He later flew a tour in 6 Group and came back to Canada with a DSO, Croix de Guerre, with Palm etc.etc. He retired as a WingCo.
After an excellent landing you can use the airplane again!