Cost runs actually about the same, jet fuel is about $5 dollars a gallon probably cheaper wholesale the issue comes from even though hydrogen produces more 3x energy per kg than jet fuel the energy density is 3x less per unit volume. Meaning you would need bigger fuel tanks per distance travelled which would require modifying the airframe to be bigger in addition to having to add insulation.

The nationwide average for Jet A is $4.53 / gal

https://www.airnav.com/fuel/report.html

Airlines pay much less for jet A than FBO prices, probably closer to $2/gal (https://www.eia.gov/dnav/pet/hist/eer_epjk_pf4_rgc_dpgD.htm).

Is that the actual current cost or an estimated one based on the cost of the electricity required?

Also hydrogen is much harder and costlier to transport and store (refueling is also not a walk in the park either) than jet fuel.

Cryogenic hydrogen is even more costly on all fronts.