Members of Hainan Airlines’ Fortune Wings Club or Alaska Airlines’ Mileage Plan frequent-flyer programmes will be able to earn double the usual miles when travelling on flights operated by the other carrier this summer.

The reciprocal double miles offer is part of a joint promotion being run by both carriers as Hainan Airlines marks the 20th anniversary of Fortune Wings Club.

Double-points earning is available for flights departing between June 1 and August 31. Members of either programme have to sign up for the offer first. Registration is already open and can be found here for Fortune Wings Club and here for Mileage Plan.

It’s worth noting these promotional miles do not count towards tier status.

Below is the accrual table for Fortune Wings Club members:

Cabin Class Class of Service Base Miles Earned Double Points Bonus Total Points
First Class F 150% 150% 300%
P 100% 100% 200%
Economy Class Y, S, B, M, H, Q, L, V, K 100% 100% 200%
G, T, R 50% 50% 100%
Non-Earning A, D, E, N, U, W, X, Z 0% 0% 0%

And here is the accrual table for Fortune Wings Club members:

Cabin Class Class of Service Base Miles Earned Class of Service Bonus Additional Bonus  Double Points Bonus Total Points
Business Class C 100% 150% 100% 100% 450%
D 100% 100% 100% 100% 400%
Z 100% 50% 100% 100% 350%
I, R 100% 100% 100% 300%
Economy Class Y 100% 25% 100% 225%
B, H, K 80% 80% 160%
L, M 60% 60% 120%
X, V, W, U, N, Q 30% 30% 60%

Alaska Airlines is also running a double miles promotion for flights to and from Seattle with partners Cathay Pacific and Japan Airlines until May 31. Both Cathay and Japan Airlines launched new routes to Seattle from Hong Kong and Tokyo Narita, respectively, at the end of March.