YYZSaabGuy

Still a fine-looking aircraft.

Guaranteed, no. Very little in this business is guaranteed. However, ancillary revenues can in general be forecast with a reasonable level of accuracy based on historic performance of a route, PAX mix (first class vs. business vs. premium economy vs. economy, etc.), stage length, seasonality, etc. I don't know why ULCCs would be any different; in fact, I would guess their revenue analytics guys/gals are pretty proficient at this stuff.