As 1st July, with no notice, there has been an increase in the flight departure tax/fee from and within Tanzania - International and Domestic flights.
These fees are NOT currently included in your airline ticket (though hopefully eventually they will be), so be sure to have sufficient USD to pay as:
USD$10/pp for International flights
USD$4/pp for Domestic flights
Understand there are signs all over the airports at JRO, DAR, ZNZ and assume Mwanza and others... but many recent fliers have been caught unaware with no funds.
For those who haven't departed on their safaris, suggest you verify with your tour operator/outfitter where you stand if you are holding flight tickets.