The RLA defines who is covered this way:
"..any company which is directly or indirectly owned or controlled by or under common control with any carrier by railroad and which operates any equipment or facilities or performs any service (other than trucking service) in connection with the transportation, receipt, delivery, elevation, transfer in transit, refrigeration or icing, storage, and handling of property transported by railroad, and any receiver, trustee, or other individual or body, judicial or otherwise, when in the possession of the business of any such 'carrier'."
Although the original intent was for this to cover railroads the act was later amended to cover "air Carriers". Given that fractional companies have air-carrier certificates, we are covered under the RLA.
As far as the right to work law goes, what it boils down to is the fact that these laws are enforced at the state level. It's a commerce clause issue, where federal law -in this case the RLA- trumps state law.