You gotta love mayor of Jerusalem Nir Barkat. He finds every way possible to promote Jerusalem.

Barkat went to the Economics Committee of the Knesset and requested changing the airport code for Ben Gurion Airport from TLV to JLM. According to Barkat, changing the codes to the letters that represent the capital of Israel would put Jerusalem back in the center and would encourage more tourism to the capital.

In addition to detailing the investments being put in to increase tourism to the capital, and pointing to the conferences, development, entertainment and everything else being done to raise the city and bring people to it, Barkat also said that he will be expanding the light rail system, in coordination with the Ministry of Transportation, and will turn Jerusalem into the most accessible city in Israel. Another interesting thing Barkat pointed out, that i had not heard of before, was that the zoo in Jerusalem is building the first aquarium in Israel.
source: INN

Gotta love him.

I don't know why it would bring more tourists to Jerusalem, just because the airport codes say JLM. It is probably just a symbolic move.

Practically I don't know if it is such a good idea to make the change. Every few years the government will change priority on where to direct tourism and will change the airport code accordingly? maybe they should change the code to ISR, rather than a specific city, since it is not even in Tel Aviv anyway...