Well, the answer is that it depends on your ultimate goals, distance of the flight, etc.
With 2 aircraft, you can do 6x weekly as a start of a 7 day schedule -
AC1 flies RT1 on 1/3/5 and RT2 and 2/4/6
AC2 flies RT1 on 2/4/6 and RT2 on 1/3/5
Then, when you add another plane, split it a little further and make room for RT3 and so on.
The other alternative that works well for single planes, if the routes is short enough (for example, to the northeast US from poland), you can just slide the schedule for a single destination on a single plane.
Day 1: 1600
Day 2: 1500
Day 3: 1400
Day 4: 1300
Day 5: 1200
Day 6: 1100
Day 7: 1000
A check: Day 1, 1100