I received a double miles promo from AA overnight. The code to register is JUN2X and the terms indicate it is open to all members of AAdvantage.

These are the detailed terms and conditions:

 

• This offer is available to all AAdvantage® members
• You must register by 11:59 p.m. CT on June 30, 2020, and before flight purchase and travel in order for your flights to count toward this promotion
• Eligible flights must be both marketed by American Airlines and operated by American or American Eagle®, booked in any purchased fare, and ticketed by June 30, 2020
• Flights booked with miles as the form of payment aren’t eligible for this promotion
• Travel booked or canceled and re-booked after June 30, 2020, isn’t eligible to earn bonus miles
• You can make changes to your travel under the original booking (record locator) after June 30, 2020, and remain eligible for this promotion
• Eligible flights must be flown between June 1, 2020, and September 30, 2020
• Flights marketed and/or operated by other codeshare partners aren’t eligible
• You’ll earn double bonus award miles for each eligible flight once it posts to your account
• You can earn up to 10,000 total bonus award miles for this promotion
• Bonus miles don’t count toward elite status qualification or AAdvantage® Million Miler℠ status
• Miles are subject to the standard AAdvantage® program terms and conditions
• American may, at any time and without notice, change, stop or end this promotion in part or in full

I wonder if other airlines will follow.

At present it’s not possible for us Brits to visit the US so it’s very useful, but for those willing or needing to be on a plane, register, you never know it might be more rewarding than usual.