Manga/Anime of two female secret/military agents featuring countless upskirt moments
Could it be Agent Aika? It features the main character (older woman) Aika and her partner Rion. There's a lot of fan service, especially panty shots and bra shots. It was released as an OVA in 1997 but was aired on several German TV channels.

The character designs practically make it impossible not to see panties

More info:


Anime News Network
Wikipedia
MyAnime List
Agent Aika Wikia