$150 per gallon is reasonable for small quantity demonstration and validation lots of fuel.
The big issue is how expensive would such a fuel be in volume production to properly demonstrate viability.
Two things to consider.
At sea an aircraft carrier must have its aviation fuel delivered via military tanker which is pretty damn expensive - it's not like have gas stations in the middle of the Indian Ocean.
One reason why the Navy might be interested in converting algae into jet fuel is that while gas stations and military supply tankers may be in short supply in the middle of the Indian Ocean, one thing that is in bountiful supply is algae.
An onboard algae to fuel conversion plant fueled by an aircraft carriers nuclear power plant could allow a carrier to operate independently it's jets for long periods without re supply at a cost incidental to the operation of the carrier as a whole.
Wars, especially air wars, are won and lost by the supply or lack thereof of fuel.
I'll give this one a pass pending more information
I will add some macro economics to the discussion as opposed to micro economics.
A shoemaker makes 10 shoes a day and makes 10 dollars a shoe or 100 dollars a day.
What happens if the shoemaker works harder and makes 20 shoes a day ?
The answer is 200 dollars in micro economics and less than 200 dollars in macro economics.
If Nike makes 10,000 shoes a day and makes 10 dollars a shoe, they get 100k a day.
What happens if Nike makes 20,000 shoes a day ?
The answer is the price of the shoes falls through the floor and they might make nothing.
Now lets talk about 150 dollar a gallon fuel.
If you need a gallon of gas for your lawn mower and gas station 1 sells it for 5 dollars and gas station 2 sells it for 150 dollars. From a micro economic viewpoint, it is stupid to pay 150 dollars for a gallon of fuel.
Now you are the US military buying 100 million gallons of fuel and Chevron is selling 100 million gallons at 5 dollars a gallon. And Algeaon is selling 1 million at 150 dollars a gallon. Why should you every buy from Algeacon ?
You might want to buy 1 million gallons because you create a glut for Chevron which might lower the price to 3.5 a gallon due to the glut. Oil is always priced at the margin.