oil distillates are the primary exports. Turkey purchases high-tech defense equipment from Israel, whereas Turkey supplies Israel with military boots and uniforms. Israeli import of Turkish vegetable products has remained steady since 2007, and imports of prepared foodstuffs, beverages and tobacco doubled from 2007 to 2011. Military collaboration In 2007, Israel and Turkey discussed the sale of Israeli Ofeq satellites and Arrow missile air-defence systems to Turkey to upgrade Turkish military and intelligence capabilities. Israeli defense companies have helped to modernize the F-4 Phantom fleet of the Turkish air force. Agreements have included air, sea, land and intelligence cooperation, manufacturing of aircraft, armaments and missiles, mutual military visits, training and exercises, dispatch of observers to oversee military exercises, staff exchanges and military know-how. Modernization of Turkey's F-4 Phantoms and F-5 aircraft – $900 million. Upgrading 170 of Turkey's M60A1 tanks – $687 million. Popeye-I and Popeye-II missiles. Popeye-II surface-to-air missiles – $150 million. 10 Heron UAV – $183 million. Arrow anti-ballistic-missiles. (Agreed in principle by Israel; approval by the United States pending.) The agreement provided exchange of pilots eight times a year; allowed Israeli pilots to practice "long range flying over mountainous land" in Turkey's Konya firing range; and permitted Turkish pilots to train at Israel's computerized firing range at the Nevatim airfield. The two navies conducted maneuvers during Operation Reliant Mermaid (the U.S. also participated) in January 1998. In September 2011, military agreements between Turkey and Israel were suspended. Turkey has frozen 16 defense contracts worth billions of dollars since March 2010. Turkey suspended a $5 billion deal for 1,000 Merkava Mk 3 tanks. Turkey also dropped Israel Aerospace Industries Arrow-2 anti-ballistic missile system worth $2 billion from bidding, with only U.S, European, and Chinese companies allowed to bid. Tourism Turkey is a popular tourism destination for Israelis. Istanbul is a 90-minute flight from Tel Aviv. No visas are required for Israelis to visit Turkey, while Turkish citizens with ordinary passports need a visa prior to travelling Israel. In 2008, before the 2008–09 Gaza War, 560,000 Israelis vacationed in Turkey, according to Israeli tourism officials. In October 2010 Israel's Tourism Minister Stas Misezhnikov encouraged Israelis to boycott Turkey as a vacation spot in response to Turkey's stance on Gaza. The number of Israeli tourists in Turkey dropped to 300,000 in 2009 and to 110,000 in 2010; it declined further to about 62,000 between January and August 2011. According to