U.S. stocks clawed back to gains in the final minutes of the trading day on Tuesday. However, fears remained after crude oil closed at its lowest level since September 2003. Delta Air Lines (DAL) shares climbed higher, despite missing quarterly estimates on its top and bottom line. The airline forecasts an improving profit margin thanks to a 50 percent drop in fuel prices. Delta is expected to save $1.5 billion on fuel in the current quarter. Viacom (VIA.B) jumped after activist investor SpringOwl Asset Management called for Chairman Sumner Redstone to step down from his role. Redstone, who controls 80 percent of voting stock, has been under scrutiny over his competency given his old age. Macy's (M) climbed after Greenlight Capital disclosed a stake in the retailer. David Einhorn's firm pushed for the company to unlock value in its real-estate assets, a position activist investor Starboard Value had previously advocated. TheStreet's Keris Lahiff reports from Wall Street.