SEATTLE (AP) -- Boeing Co.'s giant 747-8 freighter should make its first flight Monday after performing well on taxi tests and reaching a top speed of about 103.5 mph, the company said.

At 250 feet long, the plane is the largest Boeing has ever built and about 18 feet longer than the existing 747-400 jumbo jet. The company conducted taxi tests on the freighter Saturday at Paine Field in Everett, north of Seattle.

"Based on early indications, the airplane is ready to fly," said Mo Yahyavi, the 747 program's vice president and general manager.

Boeing also is developing a passenger version of the plane. It lists 76 orders for the freighter and 32 for the 747-8 passenger jet, with the vast majority from international customers.

The company says the jets will be much quieter, more fuel efficient and have lower emissions than current 747-400 models.

Boeing launched the freighter program on Nov. 14, 2005, with firm orders for 10 planes from Cargolux of Luxembourg and eight from Nippon Cargo Airlines of Japan. The jet has a list price of more than $301 million, though airlines commonly negotiate discounts.

After completing the test program, the first freighter will be refitted and delivered to Cargolux.

Boeing's European rival Airbus had planned a freighter version of the Airbus A380, the world's largest passenger jet. However, that program was put on hold in 2005 after FedEx Corp. and UPS Inc. canceled their orders, leaving Airbus with an empty order book for the cargo plane.

The freighter version is to enter service late this year. The first delivery was to have been in late 2009 and the first passenger version in late 2010, but Boeing pushed back the dates due to design changes, limited engineering resources and an eight-week strike that shut down factories.

The 747-8 freighter and passenger jets are much smaller than their A380 counterparts, which Boeing has touted as an advantage. It says the planes will cost less to operate than A380s and will be able to serve more markets.

The 747-8 passenger version will carry up to 467 people in three classes, with a range of just under 7,000 miles. Boeing says assembly of that plane is to begin around mid-2010, with the first delivery in the fourth quarter of 2011.

Boeing said in October that it was recording a $1 billion charge because of delays in producing the new freighter.

Boeing also is in the midst of a flight test program for its new 787 passenger jet, which made its first flight in December, more than two years behind schedule.