The United States and Turkey have both canceled their visa programs for nationals of each country effective immediately. This effectively stops all travel between the two countries for the foreseeable future. This move was first made by the United States after a U.S. Consulate employee was arrested in Istanbul. The Turkish government responded quickly by banning all visas for Americans indefinitely.
As of right now, no one from Turkey can visit the United States for pleasure or business. The only visas that will be granted to Turkish citizens are those for immigration. Turkey has banned all visas in the same manner.
Flights to the United States are still being offered on Turkish Airlines. However, it is anticipated that these flights will soon be cancelled. There are no airlines in the United States that offer service directly to Turkey.
In 2016, over 37,000 U.S. residents went to Turkey for business or pleasure. This was down from the 88,000 that visited in the previous year.
It is unknown at this time if there will be an end to the mutual visa ban. The U.S. State Department has not removed the application for Turkish nationals to apply for a visa or schedule an interview at this time. However, Americans seeking visas from Turkey are already being denied. If you go to the Turkish government website and click to apply for a visa, stating that you are "from United States", the website will show you a screen that says that you are applying from a country that does not have visa access to Turkey. It further advises you to visit a Turkish Embassy for more information.