Short Final: Mach 3

A few days ago, departing Minot North Dakota for Duluth in a Skylane, I asked ATC if the NOTAM for military training at Duluth had the airport closed, or whether it was open to GA traffic. He asked me to stand by for a minute, and then said, "It's closed at the moment, but will reopen in 30 minutes, so unless you are doing Mach 3, you should have no problem."