<P> Despite "Invasion!" only occurring in three of the four CW series, the event, marketed as "Heroes v Aliens", was referred to as a "four - night crossover event" beginning with the Supergirl episode . In Canada, where The Flash, Arrow and Legends all air on CTV Television Network, the crossover was marketed as a three - night event called "Heroes United". In addition, a faux classified U.S. government video was released, set approximately 70 years in the past, detailing the Dominators' first attempt to conquer Earth . A full trailer for the crossover was released on November 23, 2016 . </P> <P> The episodes, along with the rest of Legends of Tomorrow's second season, The Flash's third season, and Arrow's fifth season, were released separately on Blu - ray and DVD in Region 1 on August 15, 2017, on September 5, and on September 19, respectively . The three episodes accompanied with three Allied: The Invasion Complex behind - the - scenes featurettes, included separately in each series home media release, were also released together on a separate DVD on August 17, 2017 in Region 2, and on September 20 in Region 4 . The episodes are available for streaming on Netflix and The CW app . </P> <Table> <Tr> <Th> Series </Th> <Th> Air date </Th> <Th> Rating / share (18--49) </Th> <Th> Viewers (millions) </Th> <Th> DVR (18--49) </Th> <Th> DVR viewers (millions) </Th> <Th> Total (18--49) </Th> <Th> Total viewers (millions) </Th> </Tr> <Tr> <Td> The Flash </Td> <Td> 000000002016 - 11 - 29 - 0000 November 29, 2016 </Td> <Td> 1.5 / 5 </Td> <Td> 4.15 </Td> <Td> 0.9 </Td> <Td> 2.17 </Td> <Td> 2.4 </Td> <Td> 6.31 </Td> </Tr> <Tr> <Td> Arrow </Td> <Td> 000000002016 - 11 - 30 - 0000 November 30, 2016 </Td> <Td> 1.3 / 5 </Td> <Td> 3.55 </Td> <Td> 0.7 </Td> <Td> 1.80 </Td> <Td> 2.0 </Td> <Td> 5.34 </Td> </Tr> <Tr> <Td> Legends of Tomorrow </Td> <Td> 000000002016 - 12 - 01 - 0000 December 1, 2016 </Td> <Td> 1.2 / 4 </Td> <Td> 3.39 </Td> <Td> 0.7 </Td> <Td> 1.84 </Td> <Td> 1.9 </Td> <Td> 5.24 </Td> </Tr> </Table> <Tr> <Th> Series </Th> <Th> Air date </Th> <Th> Rating / share (18--49) </Th> <Th> Viewers (millions) </Th> <Th> DVR (18--49) </Th> <Th> DVR viewers (millions) </Th> <Th> Total (18--49) </Th> <Th> Total viewers (millions) </Th> </Tr>

Dc legends of tomorrow flash and arrow crossover