United Airlines is tapping the municipal bond market to raise nearly $522 million for projects at its George Bush Intercontinental Airport hub in Houston. The junk-rated deal will be used to finance the construction of new facilities, including a large catering operations building and a ground services equipment facility. While the bonds are issued by the city of Houston, they are secured by rent payments from United Airlines. This move highlights a strategic financing approach for the airline's infrastructure development. No specific market reaction to this bond deal was available in the immediate reports.