Getting in

• Haneda Airport: For Aihara, skip an expensive taxi and take the Keikyu Airport Line to Yokohama, then the JR Yokohama Line toward Hachioji to Aihara. Allow about 75–90 minutes and roughly ¥1,000; one transfer, reliable, and usually better than gambling on an airport bus plus a local connection.
• Narita International Airport: The comfortable, low-hassle route is the Narita Express to Shinjuku, then JR Chuo Line to Hachioji and the JR Yokohama Line back one stop to Aihara. Budget about 2 hr 15 min–2 hr 45 min and around ¥4,000. It is not cheap, but it avoids road traffic and is far more sensible than a taxi. Airport buses to Machida exist but are not a good final connection for Aihara.
• Shinjuku Station: Take the JR Chuo Line west to Hachioji, then the JR Yokohama Line one stop to Aihara: roughly 70–80 minutes, around ¥1,000, and no awkward inter-station walk. For Machida rather than Aihara, Odakyu Rapid Express or Express from Shinjuku reaches Odakyu Machida in about 29–35 minutes for ¥360; change to JR Yokohama Line only if you actually need Aihara.
• Shin-Yokohama Station: This is the useful Shinkansen gateway. Take the JR Yokohama Line toward Hachioji directly to Aihara; allow about 35–45 minutes and roughly ¥500. It is decisively easier than going into central Tokyo first.
• Tokyo Station: Take the JR Chuo Line west to Hachioji, then JR Yokohama Line to Aihara. Expect about 75–90 minutes and around ¥1,000–1,200. If arriving on the Tokaido Shinkansen, use Shin-Yokohama instead.