Do you mean flights that fly directly to Mexico from Canada?
Otherwise, you should be fine. ICE doesn't have jurisdiction over the FAA and can't just order random planes down. Especially planes from one country to another with no intervening stops in America. What on Earth would the rationale be? "Hey, citizens of other countries who had no intention of entering the US, we've kidnapped you and now you're stuck here!"
There are plenty of valid concerns and fears about America but having them ground international, non US bound flights would be a nonsensical international incident with 0 gain.