As long you haven't made cargo R&D, you may not take advantage of the following, but if you did, the read this:
I made the following calculation with my favorites planes:
On a A380, you may have 852 eco seats (maximum) and 4 tons cargo (bonus)
On a B777-200LR you may have 440 eco seats (maximum) and 20 tons cargo (bonus)
On the line CGK-LED (24h with A380) I have a demand of ±4000 eco seats and 633 tons of cargo (I made all R&D...)
The eco seat is at 3665$ and the cargo at 11772$/ton (bus=4874$ 1st=8429$)
That means that in this particular case, I can run 2 A380 with 852*2*2=3408 eco seats a day + 4*2*2 tons/day as a simple bonus : 188352 $/day
For a beginer you may divide those amounts by 2 because you haven't made all R&D, but that's still ±48k$/day you are missing for each A380
I let you calculate what you miss every single day with all your planes
My advice is to invest the minimum R&D to get the cargo availability as soon as possible in your fleet