Honestly, I'd feel better knowing it has a reserve system in case there's any issues, even if the batteries have more than enough power, beats having it and never using it, than needing it and suffering as a result.

Do current aircraft have a backup in-case their fuel tanks run dry?

There's reserve tanks or more generally reserve fuel for emergencies. Other than that there's no propulsion backup for when the fuel runs out, instead redundancy comes from multiple independent fuel tanks.

[delayed]

Current aircraft have * MULTIPLE HOURS* of fuel tanks. Compared to dozens of minutes of battery that this thing has.

Typical reserve requirement is 30 min for a turbine aircraft (45 for piston). Given the 125 mile battery-only range and the probability that it flies at at least 200 kts (230 mph), it’s pretty unlikely to hit even a 30 min reserve on only batteries. I like the design, I think they get the problem and have a decent solution for it