balaram -- I would second neophyte's suggestion on the train. I've used trains in that part of the world quite extensively. While it is not 20 times cheaper than flying (more like 2 times cheaper, should cost you about $30 one way if you choose first class, and I'd strongly recommend that), it's much more convenient. Train #5 leaves Kiev daily at 8:40 pm and arrives in Odessa at 8 am next morning, and in the opposite direction train #6 leaves Odessa at 8:20 pm and arrives in Kiev at 7:30 am next morning. Railway stations are in the centers of both cities, thus very convenient for transfers. You may want to look at the complete train schedule.