Image source: Getty Images Air Canada(TSX:AC) stock is continuing to rally for the fourth week in a row. On Monday, its stock rose 4.4% after ending the previous week with solid 7.6% gains. With this, the airline stock has inched up by 25% in February so far. Let’s take a closer look at what factors could be driving its recent gains. Then we’ll discuss whether it’s a good stock to buy right now. Air Canada stock rally On Monday, Air Canada’s sharp gains came after Deutsche Bank upgraded its outlook for the airline sector. Deutsche Bank analyst Michael Linenberg believes “COVID cases, hospitalizations, and vaccination rates are all trending in the right direction.” The upgrade triggered a rally in most airline sector stocks yesterday in the U.S. and Canada.