Hope I'm not too late in this.
Always leisurely stroll. However, you must make it look like you don't have a lot of time. This is for public perception. Seriously, if you spend more than 15-20 minutes of downtime in an airport you're a &@#%ing moron who has no life
In order to pull this off you need to stroll by people and start up conversations with them but never let the conversation continue because you have a flight to catch.
EX. "Hey, I see you're reading Sack Lunch. Interesting book I'd love to share my thoughts on it but I have a flight to catch."
or "How you doing Mac? Enjoying a cream cheese stuffed soft pretzel? I'd love to try one of those sometime but my flights about to board."
These exchanges should always be executed without breaking pace.
IMO, this is the best way to show that you are cool and calm but crap man you got places to be. HTH.