The appearance of American bombers B-52H Stratofortress at the borders of Crimea and imitation of bombing of Crimea has provocative character, and it is the element of information war. The main component in this event is the imitation of bombing of Crimea. The Russian long-range bombers have never allowed themselves such actions.
Ukraine recognising the Russian status of Crimea would be a good basis for negotiations on maritime borders between the two countries.
Another manipulative story that Ukraine impedes negotiations with Russia on a peaceful settlement. Ukraine stated that it is ready for negotiations "in any format" to restore Ukrainian sovereignty over Crimea annexed by Russia.
Russia appeals to the fact that after the annexation of Crimea, Ukraine allegedly lost any right to use the sea routes adjacent to the peninsula. However, according to the international maritime law (article 44), Kyiv has every right to use the Black and Azov Seas.
More cases about Sea of Azov here.