239741
He started his engineering career in 1957 at Cessna Aircraft Company working on the Cessna CH-1 Skyhook four-place helicopter .
 Cessna Aircraft, Cessna
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Cessna Aircraft, Cessna