Here is an abstract of an old suit filed by the Teamsters that shows what the IBT thinks of pilots who are paying:

http://www.nmb.gov/representation/deter2000/27n008.html

Quote:
IBT filed challenges and objections to the list of eligible voters. The Organization challenged the eligibility of several individuals, including twenty-two "Pay-For-Time Pilots." The IBT argued that the Pay-For-Time Pilots were ineligible because they were "temporary," paid the Carrier for flight hours, and did not share working conditions with the employees in the craft or class. According to the Organization, these individuals were not on the seniority list and could not bid for routes.
End Quote

The NMB found in favor of the IBT.