Proponent is the largest independent distributor of commercial aircraft parts, serving the MRO, OEM and airline markets for over 45 years. With worldwide inventory and staff, we operate on the global scale of aerospace. Proponent isn't just a name, it's our mission statement. With unmatched agility and service, we are focused on simplifying your aftermarket needs with custom solutions and fast, reliable delivery of critical parts. See what's possible with a proponent on your side.