TV series broadcast in USA, Probably from 1990-2010. Set in modern times, in English.
Spaceship full of humanoid aliens crashes in Alaska or northern Canada in the middle of winter... Earth radar saw the crash and sent out the military to "rescue" the survivor of the crash. About half/two-thirds, escaped before the Military arrived. I think the ship had about 150-200 aliens on board, but only 40-50 were captured (Mostly those injured in the crash).
The crash happened in the 1960s-70s, and now 30-40 years later, the captured aliens are still being held in prisoners in an isolated military base. If I recall correctly they have aged very little.
Meanwhile the ones who have escaped have blended into society and worked they way up in power/position/authority in business and politically.
I believe one of (if not The leader) was one of those who was captured and is an elderly woman. She is keeping the ones who were captured from causing trouble or making waves while coffined. But I don't think any of the prisoner were revealing anything to the humans despite being questioned for years.
I think the ones who escaped were working on how to contact home, but some of them were getting frustrated that their companions were still being held prisoners and were agitating their leaders on the outside to do something about getting them out.
I can recall 2 scenes I think were in this series. At one point a bunch of people gather in an auditorium or movie theater. It is then revealed that ALL of them are the aliens who escaped the crash. They are having discussions/arguments about how to proceed.
Another scene I remember is the US President(?) is giving a speech out doors somewhere, and hijackers/terrorists grab a airline jet and it is going to crash into where the speech is taking place. (Everyone there at the location is GOING to get killed) [I think the VP left just before the crash he may have been involved in arranging the crash.]
The aliens decide they Have to reveal themselves/capabilities. They open a portal right in front of the jet and it flies into it and is teleported about 100 miles away where it does a belly flop in the desert.