I have T-Mobile's Simple Choice plan, and while I haven't flown too much internationally, the few times I have, my service has worked seamlessly.
My plan includes 4G coverage in Mexico and Canada, and 2G coverage in 100+ other markets (with the option to upgrade for 3G and 4G rates in those markets). Looking at [1] it appears the current plans may not offer this for free anymore, but it's still available.
My plan includes 4G coverage in Mexico and Canada, and 2G coverage in 100+ other markets (with the option to upgrade for 3G and 4G rates in those markets). Looking at [1] it appears the current plans may not offer this for free anymore, but it's still available.
[1] https://www.t-mobile.com/travel-abroad-with-simple-global