No US transportation or immersion suit requirement for aviation. The Department of Interior has a requirement in their aviation guide (
http://www.oas.gov/hqtrain/forms/refguide.PDF), and the parts of the CFR that govern marine operations have requirements for immersion and abandonment suits.
Use in the commercial market is driven by company standards. We're looking at the updated Transport Canada regs for our upcoming suit purchase. Previous use has been leased suits from a North Sea provider.