[UPDATE, May 8, 2019: British Airways and Iberia upped fees on bookings outside their preferred distribution channels to $14, 12.50 euros and £10.50, effective May 31.] British Airways and Iberia said that on Sept. 18 they would increase the surcharge applied to bookings that don’t go through “an NDC-based connection or through other low-cost channels,” according to messages to travel…