Editorials Milestones June 05, 2006 Share 1 -- Hats off to the designers of the DC-9. It was in 1963 when the Douglas Aircraft Co. set about to design a short-haul twinjet, a little brother for the big, four-engine DC-8. Little did they know that they had stumbled upon a winning design that would remain in production for over 40 years.The DC-9 went through several changes in length, wingspan, range, payload and nomenclature over the years, probably giving birth to more derivative models than any other commercial aircraft in history.After it went into service with Delta in 1965, it gave rise to five basic versions, plus five variations of the MD-80, in addition to the MD-90 and MD-95. When Boeing acquired McDonnell-Douglas, the MD-95 became the Boeing 717, and production continued until AirTran last month took delivery of the last of the breed.There are about 2,400 of them, in lengths ranging from 100 to 152 feet, built for loads ranging from 80 to 170 passengers, but theyre all easily recognizable by the high T tail, the fuselage-mounted engines and the five-abreast seating in coach.Theyve taken millions of people trillions of miles, and theyre going to keep going for years, maybe decades.Not a bad run.• • • The end of the line for the 717 also means the end of the line for the Boeing assembly plant in Long Beach, Calif., which began life under the banner of Douglas Aircraft in 1941. California was once a cradle of the aviation and aerospace manufacturing industries, but its major (and minor) airlines left it long ago. The Long Beach plant was the last major commercial aviation manufacturing facility in the region. There arent many places where you can say, Here they built airplanes for 65 years.Also, quite a run.Precious cargo!We were flabbergasted to hear from a travel agent recently that a major international airline refused to book a clients toddler in a separate seat, insisting instead that the parents hold the child on their laps for the duration of a transatlantic flight.Shame on Alitalia, and shame on Italy!The airline says its policy, dictated by its governments air safety rules, provides for bassinets for infants but doesnt allow any child safety seats -- nor does Alitalia allow the sale of airline seats to children under 2.Its bad enough that airlines allow parents to hold their children on their laps, but to require the practice and to ban the use of safety seats, even when parents are willing to pay an extra fare, strikes us as bizarre. Its particularly bizarre because European industry, in general, can boast of world-class safety awareness in many areas. Italy, we are told, has fairly strict rules about the use of child safety seats in cars, which makes this approach to air safety even more inexplicable.The airline -- all airlines -- should have a system for evaluating child seats and for permitting (or encouraging) parents to use them.If Italys air safety regulators or senior managers of Alitalia were required to cross the Atlantic a few times with an 18-month old on their laps, in a coach seat, through the meal, through the movie, through the night, you can bet this policy wouldnt survive the in-flight snack.