Is the only difference between the 747-300 and the 747-400 the winglets? Could a 743 be converted into a 744 with the addition of winglets? Mark --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.481 / Virus Database: 277 - Release Date: 13/05/2003