The friendly skies are filled with a few more laptops these days. The mean number of trips taken by business travelers increased to 8.5 this year, from 8.3 in 1999, according to The Yesawich, Pepperdine & Brown/Yankelovich Partners National Business Travel MONITOR. Business travel, it seems, is viewed as a necessary evil. Fifty-seven percent of on-the-road workers said they would avoid travel completely if they could accomplish their business goals without it, compared with 50 percent in 1999. Even though they'd prefer to stay home, fewer business travelers are grumbling about taking work on the road: 32 percent say they find work-related travel a hassle, compared with 41 percent last year.