A dashed magenta line forming a circle around an airport on a sectional chart indicates:
AClass E airspace extending from the surface upward around an airport with instrument approaches but no operating tower✓
BClass E airspace beginning at 700 feet AGL
CA non-towered airport in Class G airspace
Why →A dashed magenta line (also called 'broken magenta') indicates Class E airspace that begins at the surface. This airspace surrounds airports with published instrument approach procedures but no operating control tower. Part 107 operations inside this boundary require ATC authorization under § 107.41 because surface Class E is controlled airspace.
The trap →The non-towered Class G answer treats the airport as if it were in Class G, which is the whole reason this symbol exists. Pilots who miss this pattern fly into surface Class E unauthorized.
Field note →Dashed magenta around an airport is the most common 'surprise, authorization required' moment for drone pilots.
SOURCE → 14 CFR § 107.41; FAA Aeronautical Chart User's GuideCHECKED JUL 16ACS II.A.K2EASY