A power unit for an aircraft (100, 1000) comprising: electric motors and corresponding inverters; at least one gear box associated with the electric motors and comprising gears, the at least one gear box including an oil distribution module, an oil reservoir, and an oil pump; an oil cooler and a regulator and filter; a cooling fan configured to: draw air into the power unit across the inverters to cool the inverters; and expel air into the oil cooler for cooling oil contained therein and then out of the power unit; wherein an oil path through the power unit is provided in which: cooled oil is provided by the oil cooler to the regulator and filter, which regulates and filters the oil; a portion of the cooled oil from the regulator flows to the oil distribution module and another portion of the cooled oil from the regulator bypasses the oil distribution module and flows to the reservoir; the oil distribution module is configured to distribute oil to the electric motors and the gears of the at least one gearbox, to cool the electric motors and the gears of the at least one gearbox; the reservoir is configured to collect the distributed oil after it has been used to cool the electric motors and the gears of the at least one gearbox; and the pump is configured to pump the collected distributed oil from the reservoir to the oil cooler; and at least one structural element for retaining the electric motors, the at least one gearbox, the cooling fan, the oil distribution module, and the reservoir together as a unit; wherein the power unit is implemented as a line replaceable unit, and the at least one structural element comprises a housing or first and second rails disposed on opposite sides of the power unit. electric motors and corresponding inverters; at least one gear box associated with the electric motors and comprising gears, the at least one gear box including an oil distribution module, an oil reservoir, and an oil pump; an oil cooler and a regulator and filter; a cooling fan configured to: draw air into the power unit across the inverters to cool the inverters; and expel air into the oil cooler for cooling oil contained therein and then out of the power unit; draw air into the power unit across the inverters to cool the inverters; and expel air into the oil cooler for cooling oil contained therein and then out of the power unit; wherein an oil path through the power unit is provided in which: cooled oil is provided by the oil cooler to the regulator and filter, which regulates and filters the oil; a portion of the cooled oil from the regulator flows to the oil distribution module and another portion of the cooled oil from the regulator bypasses the oil distribution module and flows to the reservoir; the oil distribution module is configured to distribute oil to the electric motors and the gears of the at least one gearbox, to cool the electric motors and the gears of the at least one gearbox; the reservoir is configured to collect the distributed oil after it has been used to cool the electric motors and the gears of the at least one gearbox; and the pump is configured to pump the collected distributed oil from the reservoir to the oil cooler; and cooled oil is provided by the oil cooler to the regulator and filter, which regulates and filters the oil; a portion of the cooled oil from the regulator flows to the oil distribution module and another portion of the cooled oil from the regulator bypasses the oil distribution module and flows to the reservoir; the oil distribution module is configured to distribute oil to the electric motors and the gears of the at least one gearbox, to cool the electric motors and the gears of the at least one gearbox; the reservoir is configured to collect the distributed oil after it has been used to cool the electric motors and the gears of the at least one gearbox; and the pump is configured to pump the collected distributed oil from the reservoir to the oil cooler; and at least one structural element for retaining the electric motors, the at least one gearbox, the cooling fan, the oil distribution module, and the reservoir together as a unit; wherein the power unit is implemented as a line replaceable unit, and the at least one structural element comprises a housing or first and second rails disposed on opposite sides of the power unit.