Lexington, Mass. ? Raytheon Co. said in a filing it may be forced to reduce its backlog of aircraft orders by $1.75 billion because of a down market and delays in the introduction of its new aircraft.

In its annual report to the Securities and Exchange Commission, Raytheon said Monday a $900 million order for its new business jet, the Hawker Horizon, “could be restructured or canceled” because of market conditions and developmental delays. Raytheon, which operates a Wichita plant, wouldn’t name the company that placed the order.

Raytheon hopes the Hawker Horizon, a long-range jet designed to carry up to 10 passengers, will be certified by the Federal Aviation Administration this year and deliveries will begin next year.

The company also said it may have to take out of backlog $850 million in aircraft ordered by Flight Options LLC, a Cleveland-based joint venture that arranges the shared use of business jets.