Issues in Flight Analysis

Why Flights Take Longer
http://www.travelandleisure.com/travel-tips/airlines-airports/why-flights-take-longer (Archive)

Are You Being Told the Truth about Flight Times?
A study which says they are skewing flight times:

https://www.telegraph.co.uk/travel/travel-truths/Are-airlines-exaggerating-flight-times-so-theyre-never-late/ (Archive)

Are you being told the truth about flight times?