I know where I remember this from now. They made a TV series of this in the 1960s and it was dubbed into English and shown on the BBC as "The Aeronauts". It must be 35 years since I saw that program ...
Yes!
It was (is) "Les Chevaliers du Ciel", The Knights of the Sky. My uncles were "brought up" watching it! Well, nearly. It was very popular and I saw replays later on.
There was a remake, or rebirth, of the series (poor) in the 1990s. And in 2007 a feature film with a poor storyline but great, great shots. Type "Chevaliers du Ciel" on YouTube and you may see various extracts and the trailer, some of which are in the links I provided above.