I have some miles in Aeroflot Bonus program, some more in the FlyingBlue (KLM / Air France) and some more in other programs, but my concern is regarding the Aeroflot and AirFrance programs. Is possible to join the miles earned in each program in just one account?
Miles are not a currency that can be moved between programmes. There are some exceptions (such as Avios, which can be moved between the British Airways Executive Club and the Iberia Plus) but this is unusual. I am not aware of any SkyTeam programmes that work like this.
If it is absolutely essential that you move the miles you might be able to convert via a common hotel partner or through some third party unofficial swap website. But it is likely to be very poor value in the first case and in the second case, a violation of the programme's terms and conditions.
You may buy flights from any SkyTeam airline using any other SkyTeam account. But you cannot merge or pool your miles together.