I saw on the Wiki a couple days ago that all FC jumps are put in a queue so as not to overtax the servers. The more ships trying to jump at the same time, the longer the prep/queue time.FDEV said that jump time can vary depending on how many other carriers are jumping, and other network traffic. It happens from time to time.
I've just this minute plotted a jump and it says 52 minutes, that's kind of bad considering it is usually 15 minutes.
Have the servers become saturated due to lack of investment perhaps?