Zeppelin scouts travel at a baseline speed of 48mph
We currently have +200% added from the Event
So why only 42.4mph when it showed 167.5 mph on the battle report?
This was on Sirens server, but I dont have time to test every game and server
Please dont try to tell me this is a 'feature' and not a bug
Exactly the same thing just happened on pirate bay http://prntscr.com/iyyql2
It IS a feature. 
The minimal travel time is 1min. If the time computed from the speed and the distance is less than that, it'll be bumped up to 1min (plus 15sec if sending from the harbour, btw). Similarly, the maximum is 24h and anything longer will be bumped down.
When your units are underway, the speed is computed from the distance and the total travel time, so 0.71mi / 1min = 0.71mi / (1/60)h = 42.60mih.
Try with a target that's more than 1min away, i.e., more than 167.5mih * 1min = 167.5mih * (1/60)h = 2.8mi (3.49mi if sending from the harbour) and the numbers should match.
