There are daily flights from Miri to Bario. To book your Miri - Bario flights, please visit MASwings website (http://www.maswings.com.my/) or call their toll free phone # 1300 88 3000 (within Malaysia) .
To get to Miri, the most common gateway is Kuala Lumpur (Malaysia Airlines and AirAsia). There are also flights from Singapore (AirAsia), Kota Kinabalu (Malaysia Airlines and AirAsia) and other towns in Sarawak.