Contrary to many American’s perception, Syria has oil and natural gas fields. Before Barack Obama decided the Dictator Assad had to go, despite winning a three way election with 10 million votes, Syria was making deals to increase oil production, which surely the Saudis did not like.
Syria has oil production of 33,000 barrels a day, placing it as #35 on the list of Oil produced per capita.
Turkey is #87.
Russia blew up the oil tankers that the US refused to attack because they are taking oil from the ISIS controlled oil fields inside Syria into Turkey.
Understand now why the Russian plane near the border was shot down?