The tax system will be probably the simple one now in use at the test world, with some adjustments. A rolling tax payment system taking into account the previous 3 years.
Very simple. At the end of every Sunday the taxable sum on P&L statement is checked; if you have recorded a profit on that week the system checks your previous profits and paid taxes over last 3 years (all profits and all paid taxes summed). If you owe money, you pay it instantly.
For example: period 1 - loss $500; no taxes paid, period 2 - loss $500; no taxes paid, period 3 - profit $500; no taxes paid (-500-500+500=-500), period 4 - profit $1000; pay taxes based on income of $500 (-500+1000=500), period 5 - profit $1000; pay taxes based on this $1000 (previous losses were covered already) ..etc
No year-end tax returns or payments or any hassle at the end of each month, and P&L statement is clear to read in this matter (will add also a line where you can see the overall taxation status for the 3 year period). Taxes paid are always pretty much correctly and there are no sudden/large payments. Only downside is that if you make a large profit now, thus pay taxes, and then make losses for a very long period into the future, the previously paid tax is not counted towards your advantage until you start making profits again. So perhaps the total taxes should be checked still at the end of each year (there basically you'd get only tax returns for this one case, otherwise it's all paid), but this complicates it again..
But in any case, as simple as possible. (...or is there something else that I missed?)
(and with regards to previous comments about week being too short interval - the aim is not to avoid the taxes by being online "all the time"; by route openings etc you cannot avoid the taxes anymore since a/c and slot purchases are NOT directly tax deductible so it's a moot point really... And for the real-life aspect, the weekly calculation is the best because it's the simplest to follow in your income statement, technically simplest also and this way also sudden large cash jumps are avoided. (salaries aren't paid usually weekly either ...) )