If Ridi & Nawawi (or others) had been known to be training on commercial, wide-body airlines, that would imply suicide missions. Otherwise Bin Laden would have more innocuous uses for pilots in his organization.
The article sort of implies that Ridi & Nawawi went to flight school in Texas & Oklahoma at bin Laden's request and expense.
This doesn't seem to be the case with Ridi, who was already a pilot when he got involved with bin Laden, according to his court testimony. (Actually Ridi is a flight instructor too.)