Twente Airport EHTW

It’s been closed when I’ve come by. Maybe you could contact the flying club?

AFAIK the airport is essentially dormant, and the only authorised users are the local aircraft dismantling firm and the local flying club. They are required to provide certain services, such as fire cover, whenever they are operating. The flying club is the only organisation accepting “outside” traffic, but it is run by volunteers. I guess they’re not able to put enough crews together to operate as standard every day of the week. Hence the 24hr PPR and the Monday closure.

Twente Airport is indeed only open to visiting traffic on the days you mentioned. The other days only based traffic can use the field because it used for all sorts of testing, like water ingestion trials, drone-flying etc. (Source).