NEW YORK: Boeing Co warned employees on Monday that it plans another round of involuntary layoffs that will affect hundreds of engineers, according to a source and a memo seen by Reuters.The layoffs are set to start June 23, and follow a prior involuntary reduction of 245 workers set for May 19, according to the memo from John Hamilton, vice president of engineering at Boeing Commercial Airplanes. Boeing did not immediately respond to requests for comment. - Reuters