When I talk about hypotheses in the future, can I say in the following way.
1. We would(could) use use own private jets to commute to work in the future.
2. There would(could) be travel agenciey that can land us on the noon.
If you want to talk strictly about hypotheses then you should use "would". Could is generally used to state possibility, but it's not excluded from the hypothesis classification.
By using "would" in the sentences presented, you're describing the action in a future tense.
If you were to use "could" instead, you'd simply be stating the possibility of the action.
You could say that, but if you're making a prediction as to the future, you would generally say "will" rather than "would." "Would" is like the Russian "-by" -- sorry I can't write in Cyrillic.
