Frequent Flier Miles

Generalizations are bad in this case. Go airline by airline.


Southwest
Points aren't directly related to miles. Some $72 fares can be redeemed for different miles. Not sure why.

Chicago to LGA  New York one way in Southwest

April 28 - $55 - 2725 points = Redemption value is $20.18/1000 miles
April 13 return - $66 - 3462 points
April 4 - $72 - 2,956-3,416 points
April 3 - $74 - 3,416
April 5 - $96 - 5,471
April 9 - $104 - 5,426
April 20 - $116 - 6,811 points = Redemption value is $17.03/1000 mile
$365 - 25,445 = Redemption value is $14.34/1000 miles