US stock index futures climbed on Monday on hopes of a coronavirus vaccine by the year-end, while remarks from House Speaker Nancy Pelosi revived bets that an agreement in Washington on a fiscal package could be reached soon. US planemaker Boeing Co’s shares rose about 1% in premarket trading as American Airlines Group announced plans to return its 737 Max jets to service by the end of this year depending on certification of the aircraft from the Federal Aviation Administration. American Airlines shares gained 0.9%. Pelosi said on Sunday that differences remained with President Donald Trump’s administration on a wide-ranging coronavirus aid package, but she was optimistic legislation could be pushed through before Election Day. Meanwhile, Trump and his Democratic challenger Joe Biden will debate for a final time on Thursday with about two weeks left until the Nov. 3 presidential election.