Complex sentence: By then, though Imperial Airways had decided no longer to transport passengers in single engined types for safety reasons and the sole Highclere was transferred to RAE Farnborough on 7 March 1926 for experimental work.
Split into simpler sentences: By then, though Imperial Airways had decided no longer to use single engined types for safety reasons. The sole Highclere was transferred to RAE Farnborough for experimental work.