Not sure what this has to do with BA aside from arriving on a BA flight, but the MPC app is available to

• U.S. Citizens
• Lawful Permanent Residents
• Canadian B1/B2
• Returning Visa Waiver Program Applicants (i.e., on ESTAs)

and available at I believe around 45 entry ports (air and sea and pre-clearance) but not every US port.

Personally I have never gotten it to connect properly at JFK T8 (the app always claims I have no internet connection when my roaming internet is just fine), but as I normally fly IB to JFK, I usually breeze through the regular queues within about 5-10 mins due to a lack of other arriving flights.