The four Gospels describe Jesus able to pop in and out of rooms with locked doors. He can appear wherever He wants to be.

The Ascension was for the purpose of the crowd, not a necessity to travel. It demonstrated to the crowd that this 40-day period was over. Jesus wouldn’t be around bodily, anymore.

They should look to the Spirit, now, which Acts describes in detail.

Once Jesus was out of sight, He would simply pop over to wherever He wanted to be.