The U.S. Global Jets ETF (JETS) was up a strong 4.54 percent on December 26, 2018, its second-largest single-day gain since the fund became available to trade in 2015. The surge came after Brent crude oil, one of airlines’ biggest expenses, suffered three straight days of losses. The international benchmark was down a massive 6.22 percent on Christmas Eve alone.Throughout 2018, it was a good bet to buy JETS after oil had been down more than two straight trading days. The ETF’s longest rally—between June 27 and September 22, when it added 15.62 percent—coincided with two separate instances of oil trading down as many as three straight days. JETS also rallied sharply, more than 16 percent, between late October and late November as oil fell for four straight trading days and, later, six straight trading days. 
More recently, oil fell for three straight days ended December 24 and is now below its 50-day moving average. Does this mean JETS is ready for another rally? There’s no guarantee, of course, that the ETF will behave as it did before. But because fuel is one of airlines’ largest expenses, the decline in oil prices could come as a benefit to the group as we head into 2019.Related: It’s Time to Reconsider Risk Thanks in part to lower fuel costs, global airlines are now projected to log their 10th consecutive year of profitability in 2019, the longest run in the industry’s history, according to the International Air Transport Association (IATA). Analysts estimate profits to total $35.5 billion next year, up nearly 10 percent from this year.“We are cautiously optimistic that the run of solid value creation for investors will continue for at least another year,” commented Alexandre de Juniac, IATA’s director general and CEO.
