Vacancies can only be offered to new-hires after they've gone unfilled on a vacancy bid. This gives existing pilots the first shot at them.

Those unfilled vacancies *MAY* then be given to new-hires but the company is under no obligation to fill them. Those unfilled vacancies expire after (I think) 90-days but can be used for multiple classes of new-hires until they expire.

Once all unfilled vacancies have expired, the company must have another vacancy bid to produce additional unfilled vacancies before they can have any additional new-hires.

When a new class starts in Denver there may be 30 people in the class but many more unfilled vacancies from previous vacancy bid(s). The company chooses which 30 of the unfilled vacancies will be offered to that specific class.

Once a new pilot has started class they are eligible to bid on any open vacancy bid. The only restriction is the seat locks from their initial award so they can't lateral to other equipment (737 to 320 or vis versa) but they can bid up (737 or 320 to 756) and they can bid other bases in their current airplane.