What will happen when the Kingdom economy begins?

When the Kingdom economy begins, everything will come under Christ's headship, as Ephesians 1:10 indicates. The earthly people of Israel and their earthly Kingdom, along with the heavenly people, the Body of Christ, will all be brought under His headship.

Les explains that the Old Testament promised a glorious Kingdom on earth—Heaven on earth with Christ as King. The King was in the midst of Israel, offering them the opportunity to enter into the earthly promises, but Ephesians 1:10 shows this could not happen until the Gentile complement, the Church, was completed. When the Kingdom economy begins, everything comes under Christ's headship: Israel as the earthly people with their earthly Kingdom, and the Body of Christ as the heavenly people with all its ramifications.

Ephesians 1:10

That in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him:

What will come under Christ's headship when we enter the Kingdom economy?

According to Ephesians 1:10, when the Kingdom economy is entered, everything comes under Christ’s headship. This includes the earthly people of Israel, their earthly Kingdom, and all the ramifications of the heavenly people, the Body of Christ. It awaited the completion of the Gentile complement, the Church.