Vajrayana Buddhism is Mahayana Buddhism combined with the Hindu Tantra Tradition.

Coincidentally Tantra is the source of Hatha Yoga .

From Wikipedia

Vajrayana Buddhism is also known as Tantric Buddhism, Tantrayāna, Mantrayana, Mantranaya, Secret Mantra, Esoteric Buddhism and the Diamond Vehicle.
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The goal of spiritual practice within the Mahayana and Vajrayana traditions is to become a Buddha by following the bodhisattva path, whereas the alternative goal for

Theravada practice is liberation from the cycle of rebirth (samsara) by achieving nirvana. For a comparison of the various practices of laypeople in the Theravada, Mahayanacontemporary Buddhist householder practices. The distinction between these traditions is not always rigid. For example, the tantra sections of the Tibetan Buddhist canon of texts sometimes include material not usually thought of as tantric outside the Tibetan Buddhist tradition, such as the Heart Sutra^[6] and even versions of material found in the Pali Canon.^[7].^[8] and Vajrayana schools see

As with the Mahayana, motivation is a vital component of Vajrayana practice, and all practices are undertaken with the motivation to achieve Buddhahood for the benefit of all sentient beings. The Dalai Lama has said that:^[9]

Tantra is limited to persons whose compassion is so great that they cannot bear to spend unnecessary time in attaining Buddhahood, as they want to be a supreme source of help and happiness for others quickly.

The Vajrayana is based on the concept of "skillful means" (Sanskrit: upaya) as formulated in Mahayana Buddhism. It is a system of lineages, whereby those who succesfully receive an initiation (permission to practice) are seen to share in the mindstream of the realisation of a particular skillful means of the vajra Master. In the Vajrayana these skillful means mainly relate to tantric, Mahamudra or Dzogchen practices. According to the traditions and lineages, the Vajrayana techniques provide an accelerated path to enlightenment (explained below). Whereas earlier (Theravada and Mahayana) schools might provide ways to achieve nirvana over the course of many lifetimes, Vajrayana techniques are said to make full enlightenment or buddhahood possible in a shorter time, perhaps in a single lifetime.