"They are so scary," Hastings told CNBC. "Everything Amazon does is so amazing. How are they doing so many business areas so well? We are continuing to watch them and be impressed with them."
"They are awfully scary, I would say," he added.
Hastings appeared on CNBC's Squawk Box ahead of his panel at the Code Conference in Rancho Palos Verdes, California, on Wednesday.
Amazon spends a little under $4 billion on content right now, RBC Capital Markets lead internet analyst Mark Mahaney said to CNBC . For comparison, Netflix is projected to spend $6 billion this year.
"[Amazon] is the number one competitive risk to Netflix," Mahaney said.
There's more competition for Netflix as Hulu and Amazon — as well as international companies like Sky and Gleam — invest in more original content, Hastings admitted. It's also encouraging more people to stream content.
"People want on-demand," Hastings said. "They want to be able to control when and how they watch. With that, we are growing a whole industry."
RBC research shows Amazon and Netflix are seen as complementary services, Mahaney said.
"We saw higher subscription rates to Netflix from Amazon Prime than regular customers," he said. "It seems like the bigger trend is the description of the big bundle."
"These are two winners of that description, Amazon with Prime and Netflix with its own service," Mahaney added.
Disclosure: CNBC parent company NBCUniversal is an investor in Hulu.