The vision of Zechariah 5.5-11 was given to the prophet to encourage the Jews that the wicked Samaritans who had been opposing their efforts to rebuild the Temple would be removed from Jerusalem and resettled back in their homeland, the land of Babylon. Unfortunately, while this interpretation seems to take into account the bulk of information better than any other interpretation, the primary problem with this understanding of the vision is that historians know of no movement of Samaritans back to Babylon. But this is an argument from silence. All we know is that historians know of no major migration of Samaritans back to Babylon in the 5th century BC, but historians cannot tell us whether or not a few key individuals were relocated to Babylon during the days of Zechariah.
My detailed answer to a more recent question posted has inadvertently directly answered this question and would be more appropriate to place here. Instead of duplicating the content here, please see the related question.
To add on to the referenced answer, since there is no evidence that the Samaritans physically migrated back to the city of Babylon, and much evidence to suggest they stayed in the land of Samaria, a refining of the interpretation and/or fulfillment of Zechariah 5:5-11 may be needed.
For Instance, assuming that the only people that Zechariah's vision can refer to is the people of Samaria and that they are to return home, a more figurative return makes greater sense to me. While they may not have physically returned to the city of Babylon, they did return their allegiance to the ruling empires of the time period. Specifically when compared to the Jewish people, according to the account of Ezra.
Also, the land of Judah at the time was controlled by Babylon consistently through the 6th and 5th centuries. Literally, under Babylon rule until the end of the 6th century and then figuratively under Persian rule. Since King Darius of Persia ended up making the city of Babylon the capital of the southern Empire, an argument can be made that this 2nd empire can also be the meaning of the Babylon reference in Zechariah. Regardless, the Samaritan people returned their allegiance to the Babylonian empire. Therefore Zechariah's vision can be considered fulfilled in this sense.
A natural follow-up question one might have with this explanation is, "Why would God give this vision to Zechariah if it would not be fulfilled literally?" My answer is that I see this vision as being very important to motivating the Jewish people to complete the Temple's construction. They were experiencing continuous interference from the Samaritans who were doing an excellent job playing politics to prevent its completion. Therefore, it may have been a demoralizing project that required a prophetic vision to overcome.