401k and B fund contributions are seperate contributions and have different limitations. B fund is percentage( delta 18%, Fedex 9% x pensionable earnings capped by the ESRA, IRS limits funded by the company. 401k Is capped dependent on age and is funded by the pilot and possibly partialy funded by the company(fedex match first $500).

On the Fedex Fidelity account statement it only shows the combined 401/B fund but you can ask your advisor and they can give you the break down of the amount in both accounts.Vanguard use to show it. I forget the reason why it show combined accounts.