Supposedly there was a “space shuttle cargobay passenger module” that could carry 2x26 people seated side by side in two rows (similar to C-5 galaxy jumpseats in cargobay). This would make capacity 60. And supposedly ‘Enterprise’ shuttle used for landing tests could be retrofitted for flight although there likely were more shuttles built than were public, making 5x60=300.

A similar cargobay passenger module was shown in one of the sci-fi space movies of the 1990s or 2000s.

EDIT: Module design may also have been 4x13 with four rows (2 sets of face-to-face). I have seen depictions of both.

Supposedly there was a “space shuttle cargobay passenger module” that could carry 2x26 people seated side by side in two rows (similar to C-5 galaxy jumpseats in cargobay). This would make capacity 60. And supposedly ‘Enterprise’ shuttle used for landing tests could be retrofitted for flight although there likely were more shuttles built than were public, making 5x60=300.

A similar cargobay passenger module was shown in one of the sci-fi space movies of the 1990s or 2000s.