I was asked to supply a copy of my flight to get a METV. However, I have not been able to contact the consulate I applied at (via mail), so I'm wondering if I need to supply a ticket departing Thailand. I have a flight booked to return back to Thailand for the end of this month. Now I'm thinking about booking a ticket departing Thailand for May. Any idea if this is what the consulate wants?

It would help if you said which Consulate you applied at.

Some more info would certainly help. Some consulates will not accept mail in applications. Do you have proof your application was delivered?

Most embassies and consulates will want at least one ticket out of Thailand to issue the visa.

OP as the above experts have pointed out. You need to state where you applied. There have been many reports from members obtaining METV. Some where the "requirements" have been, lets say, watered down. Some others needed to provide much more.