HONG KONG, Jan 14 (Reuters) - Singapore Airlines has raised $500 million in its first U.S. dollar bond issue, which the company will use to buy new aircraft as the global aviation industry prepares for a post-pandemic travel rebound. The transaction was finalised early Thursday and the price was set at U.S. treasuries plus 260 basis points, according to a term sheet seen by Reuters. The size of the 5.5 year deal was finalised after bookrunners received bids above $1.5 billion, and the bond carries a 3% coupon rate, the term sheet shows. Airlines are growing increasily optimistic travel will resume later this year as a number of countries roll out vaccination campaigns to combat COVID-19. Singapore Airlines is the first major airline in Asia to tap the global debt markets in 2021, following a rush of deals in the second half of 2020. There have been 19 deals in that time worth $17.62 billion, the largest of which was a $6 billion issue from Delta Air Lines in September, according to Refinitiv data. Global airlines are expected to refinance at least $14.9 billion worth of bonds set to mature in 2021, Dealogic data showed, while a $23.1 billion in syndicated loans will become due this year. (Reporting by Scott Murdoch in Hong Kong and Anshuman Daga in Singapore; Editing by Kim Coghill)