1. An LCA is for an individual application (not bulk)
2. Statements on job postings such as ExpressJet's simply indicate preferences, not hard requirements or a promise not to hire those not meeting the preferences.
3. The bachelors degree requirement is gauged industry-wide for similar job positions. Besides in the case of ExpressJet (and most regionals) they explicitly state that a degree is preferred but not mandatory.
4. From the data, we can extrapolate that compared to all the pilots out there being hired, extremely few are coming in via H1B and only a handful via E3s.
(Note: the data isn't the complete list of pilot non-immigrant applications. Other companies may hire under alternate job titles such as "Captain" etc. , or under titles which typically would require a degree, such as Test or Engineering pilots.)
5. I'm guessing many if not most of these hires may be through recruiters and/or referrals.