At scale???
Kerosene is about 45 MJ/kg. At 15 kW and (hoped for) 20% efficiency they can optimally create one kilogram in 15000 seconds (just over 4 hours).
An A320 burns about 2500 kg/h kerosene. For one hour of flight it takes 10416 hours to produce the fuel. To put it all in perspective... you need to scale up with four order of magnitude just to support one plane.
There are, give or take, about 10000 planes in the air at any given time, some smaller, some larger. To support all planes you need to scale up with eight orders of magnitude. To make it worse; you need space for the mirrors. With the sun at about a kiloWatt per square meter and a scale of 15 times 108, you will need 1500 km2 constantly in the sun. Or, effectively, for the mirrors alone, you need four times the area around the globe to cover daylight and at least double that to mitigate clouds, accounting to about 12000 km2. Then you still need to place all the syngas installations and other infrastructure in place.
We are now talking the size of countries here, just to support our flying addiction.
(Darn, ninja'ed by Twanky)