Tribune caption on the back, Jan. 21, 1991-- "Airports and airlines step up security because of the Persian Gulf war." Handwritten at the base of the photo, "United Airlines jet at Oakland Airport that was subject of search Wed. afternoon. See story for details. nfo sketchy at time pix turned in." Photo shows the back half of a plane. On the right side near the plane, is a vehicle that resembles a bomb unit's tank. On the side is written "Port of Oakland.