I saw this science fiction a long time ago. I recall a light plane having to land. The pilot and a woman struggling to survive in a town that has had some kind of dome placed over it. I recall scenes where they are hiding out in a cabin in the woods near the edge of the dome, and he is trying to tunnel under it. I also recall some kind of "feeding centers" in town and people being abducted slowly by the aliens. Strike any bells?
Might it be The Bubble (1966) (AKA Fantastic Invasion of Planet Earth)?
Here is a plot description from an IMDb user review:
A small prop plane flying through a rainstorm must land because one of the two passengers is about to have a baby.
When the young couple and the pilot put down in the small American town, they find all the townspeople are in a near-catatonic state. The three explore and find fallen Roman columns. They try to drive out of the town but run into an invisible barrier surrounding it. Is there anything left alive on the outside, or is this the last town on Earth? The pilot is plucked from above, is a giant alien collecting specimens? The couple find a small factory producing alien food for the townspeople. Will the baby survive if the food source is destroyed? Is there a limit to the barrier, and can it be surmounted?
I don't remember "feeding centers", but the dome and the light plane and the aliens bring to mind The Slime People (1963). Does this trailer look familiar?
From the Wikipedia entry:
The film concerns a race of subterranean reptile-men (dubbed "slime people" due to their slime-covered skin) who create a wall of "solidified fog" around Los Angeles and proceed to invade the city.