Obviously, we're talking about four nuns in habits.
From CNN.com - Nuns among six passengers kept off American flight - Feb. 12, 2004:
"Four California nuns say they were among six passengers kept off an American Airlines flight in January after crew members complained of a sulfur smell in the cabin and ordered passengers off the plane.
'I felt discriminated very much, because the four of us were taken out from that group, kept us aside, not telling us why we were there,' said Sister Tessy Pius, the principal of Mary Immaculate Queen School in Lemoore, California. She and the three other nuns are natives of India and are employed at the school.
The nuns were among the group of passengers held in Dallas, Texas, for additional screening before being allowed to board another flight to Fresno, California, January 2, American Airlines spokesman Tim Wagner told CNN.
At the time, airlines were acting under strict security rules because the national threat level was orange, or high. When the Department of Homeland Security raised the threat level December 21 from yellow to orange, it warned that al Qaeda may use international flights to launch attacks on the United States. "