American Airlines has instated new weight limits on wheelchairs on many of its flights. Some planes allow 300 lbs wheelchairs, while others allow 400 lbs wheelchairs. John Morris, who uses a 450 lbs power wheelchair, has been unable to fly some of his normal routes due to the new rule.

Read more on this topic:

https://www.npr.org/2020/11/02/929489746/a-new-rule-means-some-people-with-wheelchairs-cant-fly-on-american-airlines?fbclid=IwAR1vkSDBclJ0WWbYwVZY-rAyzqTwxEuobVm3NHmd2i1WqVEoUAv6GShdvVY

https://wheelchairtravel.org/american-airlines-policy-prohibits-power-wheelchairs-regional-jets/

UPDATE: Policy has already been reversed.  https://www.npr.org/2020/11/23/938063066/american-airlines-reverses-policy-that-imposed-weight-limit-on-wheelchairs?fbclid=IwAR3QHVZK2MukNX1GBwf_28ah2lOKH_s7GQSEtnN7q8AAlNm1U5JSgvq7nPc