Well it depends. Exactly what time-period's level of tech are you imagining here? If it's any time after the 1900's (1850's if you REALLY need to fudge history) then powered flight is a definite possibility. Alternatively, human culture could just be more advanced. Or you could pick and choose technological aspects of various time periods and throw them into an anachronism stew.

Also quick edit to CS. If the term 'science' is too modern, I can change it to 'natural philosophy'