Class D airspace requires two-way communication - not a clearance - before entry, and that requirement disappears entirely the moment the tower closes.
PatternClass Charlie airspace requires a Mode C transponder and two-way radio communication - but 'standby' alone doesn't satisfy that requirement.
PatternBefore entering Class C airspace, two-way radio contact is established only when ATC responds with your specific call sign - not just any acknowledgment.
PatternIn Class Bravo you need the words 'cleared into the Bravo' - talking to a controller isn't enough to legally enter the airspace.
PatternRadio Hangar explores Class Charlie Next Door - Appleton's Airspace, the Two-Tier Shelf, and Talking Your Way In on the Way to Oshkosh.
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