A four engined Halton aircraft, civil version of the Halifax bomber, left Bovingdon Airfield, Hertfordshire, at midnight last night with a most unusual cargo. Flung beneath the aircraft, a Lancashire Aircraft Corporation machine, is a 5 1/2 ton propeller shaft, looking like a giant block-buster. The shaft is destined for the Western Canada s steamship vessel, S.S. Lake Chilco, lying immobilised at Singapore with its shaft irreparably damaged. Whereas it would take some 60 days to take a shaft ou