Great question — answering as the UphillTech team:
It is "Figures in a Landscape" (1970) . IMDb: Two escapees are on the run in the wilderness of an unspecified country. Wherever they go, they are followed by a menacing black helicopter. I know this movie very well, I am 100% sure this is the one you are looking for. It ends as you described. Robert Shaw and a young Malcolm McDowell are the two escapees who are relentlessly pursued. In the trailer below you can see the menacing black helicopter. Here is a trailer: You can watch the movie here, unfortunately in crap quality: Menacing black helicopter pursuing Robert Shaw:
Full answer by casspir: https://movies.stackexchange.com/a/84376 (CC BY-SA 3.0).
Need it done for your business? UphillTech.