In the AFD there is occasionally a ‡ symbol after the operating hours for control towers (and other time information) like what's shown below. What does the ‡ symbol represent?
StallSpin's answer on the recent question about VFR traffic patterns has got me thinking about the "Remarks" section of the Airport/Facility Directory. We are all taught in training to review the AFD entry for airports we intend to visit (part of FAR 91.103's "become familiar with all available information" requirement), and to comply with any restrictions noted - typically things like "no touch-and-go landings", "Standard traffic pattern required of all aircraft", "Prior Permission Required for jet aircraft", etc. Aside from it being The Right Thing To Do, and avoiding the possibility