Airline stocks were suffering a broad selloff ahead of Monday's open, amid a big drop in the broader stock market and as a surge of the delta variant of the coronavirus that causes COVID-19 increases fears of potential travel restrictions. The U.S. Global Jets ETF /zigman2/quotes/207744796/composite JETS +1.05% sank 3.6% in premarket trading, putting it on track for a sixth-straight daily decline, and to extend a seven-week losing streak through Friday in which the ETF has tumbled 16.5%. Among the ETF's components, shares of American Airlines Group Inc. /zigman2/quotes/209207041/composite AAL +1.13% slumped 5.2% premarket, after sinking 18.6% amid a six-week losing streak; United Airlines Holdings Inc. /zigman2/quotes/205037281/composite UAL +1.56% slid 5.1%, after tumbling 21.1% amid a 7-week losing streak; and Delta Air Lines Inc. /zigman2/quotes/200327741/composite DAL +1.82% dropped 4.2%, after losing 13.8% amid a 5-week losing streak. Elsewhere, shares of Southwest Airlines Co. /zigman2/quotes/201071949/composite LUV +0.85% gave up 3.8% premarket, JetBlue Airways Corp. /zigman2/quotes/207639051/composite JBLU +1.91% declined 5.4% and Spirit Airlines Inc. /zigman2/quotes/205782179/composite SAVE +0.66% fell 5.3%. The selloff in air carrier stocks comes as futures /zigman2/quotes/209948968/delayed ES00 -0.31% for the S&P 500 /zigman2/quotes/210599714/realtime SPX +1.46% dropped 1.3%.