Updates May 4 story with shares in paragraph 2, background on the industry and jet delays in paragraphs 4 and 7 May 4 (Reuters) - Air Canada AC.TO on Thursday raised its full-year forecast for core profit, citing a stronger-than-anticipated demand environment and lower-than-expected fuel costs. Easing restrictions spurred international travel demand, helping carriers to mitigate cost pressures even as rising inflation is making leisure activities more expensive. Despite a looming recession, major North American carriers remain confident of filling up seats on planes due to a constrained capacity and a shift in consumer expenditure to servic