NRT to LAX flights in August?

I bought my girlfriend (Japanese) a flight from NRT to LAX, for August 10!

It�fs a one way ticket, but in October 1st I�fll buy her return flight for October 4!

I have 2 questions:

1st: is this allowed or do I need to buy her return ticket before she comes to LAX!

2nd: is it possible for the flight to get canceled? :( due to COVID or whatever ?

What are the rules for US immigration. If she does not have an onward ticket the airline may deny boarding if she cannot show onward travel. That is how it works with some countries - like arriving in Japan. As for USA - check the rules that apply there.

It is possible for any flight to get cancelled, at any time, for basically any reason. Covid significantly raises the risk of this happening. More flights have been cancelled in recent months than they have during basically any other period of time since the beginning of commercial aviation. Maybe WW2 had more, but you get my point. I suggest making contingency plans ASAP.

What airline did you use?

You and your girlfriend should be aware of the risk of being strictly forced to stay indoors right after arrival. For example, in spring, many people coming into Japan had to sleep on card-box beds inside the airport. Similar things can happen before you get to see her. You need to check with your authorities well rather than to ask anonymous internet users like me. Regardless, I truly hope that things will turn out for the better in Los Angeles. Hugs.

many people coming into Japan had to sleep on card-box beds inside the airport
Apparently they've upgraded the process to using nearby airport hotels for Narita arrivals. I know someone returning to Japan in a few weeks and they have been told they will have up to three days to wait for their PCR test results. Then 14 day quarantine.

I'm sorry if my previous comment was misleading. Japan is currently much more relaxed compared to how it was in spring, in terms of Covid.

What I'm saying is that this unpredictable virus situation may change at any time until vaccination and medicine are distributed enough. If it so happens that the situation gets worse in August, either in Japan or California, your girlfriend may have to risk something.

This is a time when no questions can be answered for sure, and a time when you need to consider your risks while traveling or meeting people. That's all I'm saying.